These look promising in a prebuilt set. 1,620 grams isn't bad. $900 MSRP is definitely steep for alloy wheels though.
http://velonews.competitor.com/2012/...ability_265099
I recommend STRONGLY against buying Salsa Delgado Race 29er rims. Cross tires will not seat properly on them for me. I have tried a few different sets.
Unmachined A23 or H+Son Archetype would be good choices for a clincher build.
I wish there were better hub options out there. Hopefully that's coming soon.