I put Harley Deuce style risers on my Speedmaster that have a 6" rise and 2" pullback. All cables and brake lines fit, but I did have to move the throttle cables to the right side of the frame.
Here's the thread with all the particulars and pics. I bought mine off of ebay for something like $50 total.
With a few thousand miles on them now, I'm glad I made the change. Much more comfortable for me than the stock risers.
