These seem like a great deal, though such low spoke counts make me nervous: http://www.neuvationcycling.com/product/neuvation-m28x-aero-set-black-1500.htm
On the lower end from Bilsko’s link, I’m not sure what to think of Origin 8 hubs with sealed bearings or just Shimano 2200 hubs, both with CXP22: http://www.bicyclewheels.com/merchant.mvc?Screen=CTGY&Store_Code=B&Category_Code=RWO These would be good because I could keep the current 7-speed (with a spacer) until I’m ready to upgrade the shifters.
Just about everything I’ve found will require going from 126 spacing to 130. A 126 with 7-speed freehub cassette seems to be the least common wheel out there.