1 - it doesnt have the screen (it was hard enough to try to port it to VGA, but QVGA just isnt worth it...)

2- It doesnt have the Processor (we have a hard time getting it to run smoothly on the TP2 with a well optimized 528mhz CPU, i cant imaging how much it will drag on a 400mhz)

3- it doesnt have the RAM (part of the reason it has its speed issues with the TP2 is because it was designed for a device that has over 100MB RAM more than us, it will defenetly murder a 128MB)

hope this clears up some, sorry

PS: you can try Android with SenseUI. I saw a build on XDA just released that has it running full speed and no lag whatsoever with almost everything working