Which full-carbon wheels (brand and model) are optimized for climbing?

I rode 404 carbon clinchers for a few hundred miles and have since concluded they're not optimal wheels for continuous and hurried climbing.  My personal preference would either be: 1) Zipp 303 tubulars 2) Campagnolo Bora Ultra (or whatever the current model is) Riding the Boras on a Pinarello Dogma was a blissful experience for both climbing and descending.  However I feel wheels with a modestly grander aero profile offer more versatility, hence I now own 303 tubulars.  The wheelset performed with aplomb during a week-long Tuscan bike tour (mostly rolling hills, crosswinds, short 12% climbs).

Mavic R-SYS ... which have carbon spokes and alloy rims. What comes up must go down. Descending on carbon rims is tricky, especially for an amateur; alloys have a better braking surface. I have ENVE Composites (tubs) for racing, they are light and accelerate well on hills and elsewhere but I once delaminated an ENVE rim coming off the Galibier. Sheer drop one side, cliff face the other side, if I had come off it would not have been pretty! Thankfully the rim was under warranty otherwise it would have been an expensive replacement (pros don't have to worry about that!) Seriously, avoid deep section but consider lighter alloy wheels if you are an amateur - there's not much difference going up and you are safer on them coming down.

About the only thing that would get me out of my Mavic Ksyriums (which are totally awesome) would be the new Mavic Cosmic Carbone Ultimate... http://www.mavic.com/en/product/wheels/road-triathlon/wheels/Cosmic-Carbone-Ultimate

In what sense did you find 404s to not climb well? How steep were the climbs? You can use http://www.analyticcycling.com/ to model when deep carbon wheels will be faster, but generally speaking they are faster for almost all climbs in typical races in America. I can see using 303s for crits and circuit races with short extremely steep climbs, but 404s will outperform in flat crits and circuits and most road races.