I'll second the recommendation, although I'm no heavyweight at 145 lbs. I bought my set used, from the BF classifieds. They are a cross build 50mm clincher, 28/24. Total overkill for me, but they are my only training wheelset, and they do pit duty as well, so they have to be rock solid reliable. They are.

If not psimet or other custom wheelset, I'd recommend that you go with a heavier build. November calls them a side of beef. Zipp calls them a cyclocross wheel. Lighter wheels shouldn't collapse under your weight but the heavier build will last longer.