I've found myself pondering the same question. Here are my expectations for the Nintendo GS (Grand system, which I think will be Nintendo's successor to the DS.)
Hypothetically, if Nintendo keeps going back and re-using the initials of old systems (or system add ons) that didn't quiet work, then the next system to use a name like that should be the.. VRB (I think.. was there a failed Super NES add-on?)
For those that may be lost, the initials DS also stand for "Disk System", a failed device that was going to hook into the original NES, so that more memory could be added to games, to make more things happen (like crystals growing back after being cut with a sword).
On a side note: the Legend of Zelda would have been one of the first games to utilize the DS.
