Like the worksman bikes but dislike the bent TT? Look at the worksman m2600 with the 20" seat-tube and straight toptube:
I ride a Worksman INB; got it set up as a faux-klunker, ride trails with it (not much is stock, save the frame, BB, and i think the seatpost) and i weigh about 235-240lbs. I'm riding real singletrack on it. Frame seems really strong.
+1 to what Nightshade said about the stock seat, but know that you'll also likely need to pick up a new saddle clamp, as the stock worksman saddle has square rails, and the seatclamp won't accept a saddle with normal, tubular rails. (Clamp oughta cost you <$5.) Also, the stock pedals are absolute garbage; pick up some all-metal 1/2" VP pedals for $10-$15