What aftermarket cooler would fit in a Antec 200 Case?

Anything that is less than 200mm tall, I would shoot for 150 to 160mm tsll since you have the motherboard, mounts, etc that take up some distsnce.

So.... anything that is around 150mm should suffice. Possibly larger. I have a CNPS 10x (160mm) cooler in a case with those dimensions and it fits fine, but kinda kills the airlow in the case since it (IMHO) is too big of a cooler for the case.
 
There are several refurbished V8 and V10 you can purchase right now for a much lower price with 30 day warranty.

http://www.cmstore-usa.com/v8-nickel-plated-copper-base-aluminum-fins-8-heatpipes-cpu-cooler-refurbished/