Short of carbon fibre rims. Other than that strength and lightness rule. The rear hub is going to be approx £350. I am not going to spend bizarre money when good money will do the same thing. The rims have to be UST or tubeless.
I also want to buy a wheel building rig and build them myself. Any tips on building would be appreciated.
With regards building them yourself, my recommendation would be to get a cheap set of hubs and rims, plus a couple of boxes of spokes.
Practice, practice and practice some more on those. Wheel building is not simple in the slightest, and I would imagine is virtually impossible to learn well remotely. I was trained by an ex pro team mechanic, and it took several goes to get it right, even with constant supervision.
It's the little things - alignment of valve hole, even tensioning without stretching the hubs or rims, dishing it correctly and stressing/destressing the rim during the build.
Seeing as you're getting pretty much the nicest hubs out there, but the build is everything. I wouldn't build my own wheels now, even though I've built hundreds - I haven't done it in ten years and they wouldn't be any good at all without that practice.
Don't want to put you off - I loved building wheels, probably the only truly handcrafted element of a bike. Bloody theraputic when you know what you're doing, bloody stressful and expensive when you dont!