Try a 29er SS, particularly the Redline MonoCog. You'll have to drop a few teeth on the rear cog for street use. If you don't dig the SS in Boston, Redline makes a 8-speed version of the same bike, called the D440.
I found the the right handlebar and tires made one helluva good commuter that I can use to plow over potholes, over curbs, and jump off curbs.
This is my SS MonoCog on fat slicks, with Origin8 Space bar and Nuvinci CVT hub. Actually, the only stock parts left are the frame, fork, and seatpost. It worked fine for commuting when it was a singlespeed...
