I think i will be getting a nimbus and upgrade to a kh frame at some point later on.(a kh frame will fit a nimbus wheel and hub right?) what about the quax trials?:
http://www.unicycle.com/unicycle-com-12-days-of-christmas-sale/qu-ax-20-inch-trials-unicycle.html
kh frame should fit nimbus wheel and hub.
I know for a fact gravity impact frame fits those too.
qu-ax trials are bomb-proof, but incredibly heavy, at something around 17 pounds. So go for the nimbus, in my opinion. Unless you happen to go find a second-hand kh trials in the trading post.