TT wheels should be aerodynamic and to hell with all other considerations. They are not meant for high mileage so here is what I have done for my TT bike. I found a U.S distributor with 12H and 16H Shimano Dura Ace 7700 12H hubs. I could use Royce and a few others in this low drilling but Shimano Dura Ace a a bit cheaper. I have laced to them to 88mm deep carbon tubular rims from my usual carbon rim supplier. Sapim CX-ray spokes have been used. Getting the wheels straight is not easy but they are straight (~0.4mm of wobble it the best I could do) with even tension which shows how good the rims are. Weight of the rims is 500g so the complete wheels are not heavy at all.
They are perfect I think and cheaper than buying something of the self from one of the usual factory suspects. No worse in performance either.