Any good multi speed XC bike can be made into a SS rig. The easiest (and cheapest) way to do this is to find a gear that you're OK with in all situations and ductape your shifters so you can't shift. If you find that you like it great- there are conversion kits availiable. However if you don't like it you're not out any money or stuck with a bike you hate.
Don't get a singlespeed just because it's trendy. That's just plain stupid.