I ride a surly lht. I'd recommend asking the guys at surly, they are really helpful, in a very non-pushy way.
the S&S couplings are fairly standard, but I have never had a bike with them. the cross check and the current lht I've ridden a few thousand miles on (both) are excellent.
I guess your main problem will be sizing, as you'll struggle to get a test ride. or even see a built up frame.