Ride Engine? I bet dollars to donuts it still rides up though...
I've got a Mysyic Star (hybrid) and a Dakine Renegade. The Star is more comfy as it rides up at a slower rate due to the seat part, and the seat is low profile so the lower body is much more free for airstyle tricking.
Mystic Strappies look like a good solution, but I've been waiting over six months for the local shop to deliever on them
The other thing is the Battle Belt/Power Belt etc. Dakine ones are really elastic and strap down tight; I find this is vital for stopping the Fusion riding up into wedgie land. The Mystic has much less stretch/return and no secondary strap.
When I looked at North harnesses a few years back, the belt was just a neoprene flap -- no stretch. Waist size must be a perfect fit to the harness or gtfo. With the Dakine, you can wedge yourself in even when you're way over the waist size.
OR Session? Waist harness with leg straps basically... I have an XL but haven't used it yet as the straps arent long enough :o I can measure it if up if your waist is smaller than mine.