I cleaned up the stock exhaust and mounted it up last night. It isn't my favorite look, as it seems to be about 6-8" too long. It has the expansion chamber shape built into it, then a muffler chamber at the back that also contained a spark arrestor. It isn't terrible, just not my favorite.
It does tuck up nicely to the frame, and even has a notch to clear the rear shock. So My leg has tons of clearance when sitting on the bike.
If I get lazy enough this weekend, I may sketch up a different design, with a fatty expansion chamber shape.