I bet Gavin got one or two of the prototypes and is digging into it as we speak. I hope we get a status report soon.
No, I don't have a prototype.The hardware is real and very cool, but they've got a lot of work to do on software and user interface and manufacturing process and marketing and distribution and.... . Expect the design to change before you can actually buy one. And like all really innovative projects (and to quote the MythBusters) "Failure is always an option."
Answering detailed questions about exactly how it works right now would be a waste of time, because I think before it ships most of the answers will be different. The meeting in Vienna was for bitcoincard to get early feedback on whether or not they're headed in a good direction.
RE: why would you want a bitcoincard versus just using your cellphone: I personally think you'll want both; I'm trying to convince them that the bitcoincard could be a perfect "second device" for multisignature transactions. Cell phone viruses and trojans and malware will be the next big wave of security vulnerabilities.