Making a RPG on your DS or DSi system would just over power the database and ruin you DS/DSi. For an example, the DSi Browser is a huge file and the DSi still has problems there and now with it. Just think about, how big your memory would have to be, or the memory of you SD Card (Approx 30MB, so $140). Also for sale in the Nintendo shop, alot of points or game card over $150.