So you have a very beefy polo wheel already built for your rear wheel?

My suggestion is to find a matching one, if you intend to do polo, dick around town or FGFS riding, but then you wouldn't want a Leader 722 frame. I'm assuming the 722 is more of a traditional track frame, and not going to put up with FGFS style riding. I may be wrong.

Velomine offers the best deal on wheels, where you can pick up a set of these for $129.

Frame is where you're going to have to invest some money, imho. If I was building up something with $1k and I've already thrown $150 (129+shipping roughly) at the wheels, I'd buy one of these for $275.

Just a cheap crank, such as this, works.

Hell, that leaves you just about $500 for your brakes, stem, BB, seatpost, saddle, chain, bars, bar tape. Hell, you could make some sweet choices (like a Phil Wood BB) and still have $250 for the above components.