I'm looking for a new frame for my commuter as the one I have is a touch small (it's my old mtn bike from high school). I was going to get the Surly Troll frame (orange one) but I can't find one in my size. So I'm looking for alternatives

I want a frame that will support 26" wheels. Plan on a single chainring and 10 speed cassette. I think the wheels support disc brakes so that would be ok also. Just planning a nice flat bar general rider / commuter.

What are my alternatives to the Surly frame? Would like to stay under $500 or so