I bought 'qrko.de' for nearly the same purpose: URL shortening with bit.ly style analytics but with built in QR support (and maybe user-agent tracking. It would be interesting to see the device market share for code scanning)
I'll probably still build it; it bums me out the the goo.gl shortener is semi-closed.
Dammit!
edit: I am even in mid-process of acquiring a .et domain so I could've had http://mark.et/whatever. Gah!