I have an 11-32 10 speed IRD cassette that's Shimano compatible. Since I have a compact double with a triple front derailleur, I didn't need a MTB rear derailleur.

http://www.interlocracing.com/cassettes_steel.html

I have this on my road bike. Sorry I don't know if it will work on your cross bike or not, but worth checking out as an option.