Has anybody tried it, specifically on the 5500? Is touch typing possible? Are there driver issues with the various ROMs?

I'm finding my Micro Innovations IR keyboard a little too compact for my sasquatch hands. It looks all tiny and slick when its folded up, but I can actually type faster on the thumb board.

Any other suggestions would be appreciated.

I have one. At first I was very pleased with it. Touch typing is possible (although I would describe the action as a little spongy). I really like the sealed keyboard. I have switched to Targus, however for three reasons:
1. the FX wire is too short
2. the driver is very sensitive to changes in the ROM; when I loaded some Opie lib's, it ceased working
3. the keys are a little scruntched (Targus has more of a full sized key set)