Back in 2003 the Tapwave Zodiac, a PalmOS based (entertainment?) device hit the shelves!  My younger self really wanted one of these, since I didn't have (nor did I want to have, at the time) a Gameboy Advance. I was going to write something more extensive about it, but I found an LGR review the other day that gives a rundown of the device.  All things considered it seems like an interesting device that was poorly implemented, and it failed to prognosticate certain things (like the need for wifi!)