just leave the wheels and run the MTB bars , and it's a 'hybrid' and a whole section of devotees :

here .. http://www.bikeforums.net/forumdispl...ybrid-Bicycles.

narrower 23 wide tires and it's a'fitness bike' ..

If cantilever brake bosses on the frame, they wont be useful any more

a replacement wheel set with Drum brakes will work..

I have such a wheel on my MTB-Studded tire , bring it out when there's Ice on the roads bike.

[yes , I work on V brake bikes often. I happen to like the function of the Maguras better ,
had mine 15 years , all Ive needed was to snap in a new set of brake shoes when Worn .

they literally snap on the slave piston ends .. ]