I need to do a little research, I haven't really got a particular one in mind. I want something that is relatively simple to put together, and maybe even adaptable to different size disk and wheel combos.
Ultimot i have heard of, so will look at them further.
A major drawback of the HP2 is the sheer mass. So any solutions for lighter weight is a good start.
I might look at several ideas, even if there are setups already out there.