Nintendo got quite far with the 'DS Lite XL' design, they even got as far as producing a case mould and conducting development trials. However, the DS Lite was doing so well at the time they decided to put the design on the back burner. Back in 2007 sales for both the DS Lite and the Wii were going through the roof and Nintendo's Iwata decided it would not help matters if they released yet more hardware at a time when they were struggling to manufacture their existing consoles.
The 'DS Lite XL' as it would have been known was specced with 3.8 inch screens based on regular non wide-viewing angle LCD screens. Compare to the wide viewing-angle, 4.2 inch screens of the DSi XL, this was not as big a step up. The decision to go with smaller, standard LCD screens was due to the prohibitive cost of this LCD technology at that time. By 2009 the cost differential of standard versus wide-viewing angle LCD's had narrowed, enabling Nintendo to go with the larger and more viewable screens.
In 2007 when Nintendo started work developing the new DSi console, they toyed with the idea of releasing two versions, a large one and a small one. Later on it was plain to see that it would be almost impossible to produce two version of the DSi simultaneously and the DSi XL was put on the back burner once again.
When Nintendo bosses finally gave the go ahead for the DSi XL project, they had a dilemma on their hands. If they wanted to save money, they could just scale up the DSi case and produce a larger version of the DSi, but if they did that they risked people saying it was just a bigger version. Clearly they had to do something different, which meant a total redesign of the DSi case.
Traditionally when people are finished with a handheld they pack it up and put it away somewhere. The design team didn't want this, what they wanted was for people to feel they could leave the DSi XL open on a tabletop, almost like they would with a laptop.
To achieve this goal they decided to redesign the entire top panel. The corner radius was increased, but this made the case appear 'enormous' (to quote Nintendo designer Fujino). To improve the looks of the top panel, Fujino found that attaching a polished top panel improved the design, making it look both smaller and neater. After the raised clear panel was added Fujino remarked on how it resembled a clear bowl of water.
Because the DS, DSi and DSi XL have moving parts the physical design is just as important as the electronic design. The hinge on the original DS Lite was very prone to breaking after the console reached a certain age. In making the panels larger more stress would be placed on the hinge, and more stress placed on the screen panels themselves. It was clear that Nintendo had to make the DSi XL more rigid to cope with the increased size, but they had to do this in a way that didn't add too much weight.
All Nintendo handheld console have to go through a drop test, where the device is dropped from a set height to test if it survives the drop. Getting the larger, heavier DSi XL through this test took time, but by June 2009 the DSi XL prototype was passing this test most of the time. When they moved into the production phase in China they hit upon major problems with plastics, solvents and inks that took almost 3 months to solve and involved them making between 10 and 20 thousand top panels.
Apart from the obvious benefit of larger screens, the DSi XL has been made more accessible in a number of other ways. For example, the Power button is now bigger and easier to use and the volume control has also been made easier to adjust. The lid is easier to open as you will see if you look at the device from the side, the DSi XL is shaped like an 'inverted trapezium', this makes opening the lid that little bit easier.
Delays in the physical design process didn't leave much time to mock up colour schemes for the new device. In the end the colours were chosen from just 20 samples. 3 colours were chosen, wine red, dark brown and natural white (natural white was not released for the UK market). At this stage you would have thought that Nintendo would avoid doing any extra work, but designer Fujino decided to make the DSi XL two-tone. He had originally wanted to do this with the DS Lite and the DSi, but found it did not work for the hinges. This was not the case for the new DSi XL hinges and for the first time it was possible to create a two-tone hinge.
With the previous DS consoles, the hinge enabled the console to stop in just one position, around 55 degrees. For the DSi XL Nintendo added a 2nd position at 120 degrees. This made it easier for people to use the new console on a tabletop, which was one of the original design goals.
Despite using the same speakers as the original DSi, the DSi XL actually boasts improved audio clarity and loudness. The designers were able to achieve this by changing the size of the speaker enclosures. As with any speaker, to get the most sound energy out of it you have to put it in a speaker box. The increased form factor of the DSi XL enabled the designers to make these boxes larger which in turn produced more volume. They also wanted people to be aware of where the speakers actually were, so instead of using a single slot as they did with the old DSi, they cut seven small holes in front of each speaker. The speakers are now plainly visible to the user.
As well as the conventional built-in stylus, the DSi XL is supplied with a larger pen style stylus. Fujino admitted to designing the new larger stylus in secret. Having been given no design requirement for the new stylus, he decided to go ahead and design something that would almost certainly be needed for the new desk friendly device. He based the new design on a pen and was able to match the two-tone colour scheme from the console. The clip seen on the side is not intended to clip onto your pocket, it is simply to stop the 'pen' rolling away when placed on a table.
The original DSi was shipped with two preinstalled applications, Flipnote Studio and the Nintendo DSi browser. Nintendo designer Iwata decided to install two additional pieces of software, one being a DSiWare game, Dr Kawashima's Little Bit of Brain Training: Arts Edition and the other being an application, Dictionary: 6 in 1.
Iwata chose the Brain Training title as he felt that many people that purchased a DSi XL would not know how to download games online from DSiWare and he was very keen to get them to try a Brain Training title at least once. Iwata thought that the dictionary application would further support the tabletop gaming concept, as people could leave the DSi XL open on a desk for when people needed to lookup words.
Nintendo mused of several names for the new DSi, the DSi Deka was one of them. Deka meaning huge in Japanese. Other names included the DSi Comfort, the DSi Executive, the DSi Premium and the DSi Living. The problem they had was finding a name that sounded right in both English and Japanese. In the end they decided to take the naming convention from something that is pretty much universal, clothing sizes. In English a large size is referred to as XL and in Japan LL. Nintendo weren't entirely happy having two different names for their new handheld, but in the end they decided that XL / LL was a good compromise.