Dragracer,

Timbuk2 has a cell phone pouch available at Excel sports
Performance has a cell safe which is water bottle sized
and padded.
Topeak makes pouch that clips to either stem or seatpost
(also available at Performance).
If I had to I'd go with the hard case.
I just carry mine in back pocket (but then I ride road
only).
Hope this helps,

Marty