Please excuse me for being an ignorant newb here... but what is stopping people from just making a wallet file encoded in a QR code?
private keys are 256bits long. default wallet generates 100 pool keys plus whatever keys you've manually created - so say, 110 keys. That's 3250bytes.
Maximum data storage of a QR code is 2953 bytes1
Will
But this won't work for BitPay, because it is not a fully bitcoin node, so some web service would have to offer a "private key spend coins service" it could use.
working with bitcoin uri, just containing the address and a web service like instawallet.org is simple, easy and fast. I like it for smart phones.
I am working on a BitPay clone, that would be easily portable to android and Iphone (well, don't know what the apple market will say
