Originally Posted by streetlightpoet

Cannondale bad boy ultra. It'd be kind of expensive, but comes with 700c and skinnies for the street, the fork has a lockout, and has clearance for some 26" wheels and tires when you want to hit up the singletrack. Discs means no brake adjustment needed between the two sizes, and I believe it has rack mounts. I've been eying one for awhile now. If you didn't like the flat bar you could also swap them out for something like Salsa's dirt drops.