That's a very solid way of doing it. Any ideas what subforum or site would have the most arduino programmers?
I conceived of this idea with the arduino since I know about it from my friends, but there could be other platforms that would make this simpler or faster to develop. I'd probably want to stay away from mobile devices since they're non-dedicated and I'm guessing that trojans/rootkits can be written for them to target BC users
You don't need to know much for the arduino part. Arduino is very easy to program for and the device won't do very much. Anybody who knows C should be able to get it going. I think the harder part is patching the bitcoin client to do the transaction import and export, and getting that accepted and integrated into the GUI. I did see some guys on the forum here who said they have Arduino experience. Some google searches would probably find them all.