you don't really need a track bike although it'd be very cool if you found one. A track bike has muy steeper angles, rear facing rear dropouts, and no place to mount brakes. A road bike is much less twitchy on, well, the road, and if you find one with horizontal drops you can get the chain adjustment that you need. A complete bonus is the hole in the front fork for a brake. EBay has about a million of 'em every day - or post your size and see if anyone here has a good candidate for you.