WTB: Rear wheel FlipFlop

I am looking to complete the build of a cyclocross bike and looking for a used (inexpensive) but good working rear wheel that can run freewheel for cyclocross and fixed for commuting. 700c. I'm 200#'s, so durability is more importance than speed until I can get down to my ideal weight of 120#'s. Anybody? Email me.