I've heard that porting the GUI/IDE will not be impossible, but the Java is the hardest part.
As for the devices needing USB, most of them come with a standard Mini-B, or FTDI input, which the connector for that is just a Mini-B as well.
The devices can also been programmed via BlueTooth (for those with the spare cash to buy a BT Arduino).
I have attempted to port the GUI myself, but I've become far too confused to understand what to do.
I have installed the AVR/ARM toolchains... It's just too confusing for me. As a programmer, all I understand are IDE based languages, that you just hit the compile/run button. Like RealBasic, VB, (OLD!) Borland Builder-X, Wiring & Arduino Language.
All this new stuff is far beyond me!