Check out TAT[0], they make incredible looking mobile UIs. Also check out the concepts from the Nokia design team[1].

[0] http://www.tat.se/conceptlab/

[1] http://www.youtube.com/profile?user=NokiaDesign

(Just realised I'm posting far too much in this story. Mobile UI is a great passion of mine. I think it's been downhill ever since the Nokia 3310. If any one else is passionate about improving the mobile user experience then please contact me at [email protected], I wish to pursue a startup in this area soon)