The current difficulty with the CE platform is that TI hasn't given us the signing key for apps. Because of this developing large applications like TI-Boy is difficult to implement properly. Straight up porting TI-Boy will be difficult because it will also have to be modified to run as a program and pull the rest of the data from somewhere, instead of just running from one large application. You'd also want to make it take advantage of the extra features that the eZ80 gives you.
It would be nice to have, but nobody has taken the time to tackle porting it yet.