Laura, I've got a set of Velocity Dyad 36H rims that have been bomb-proof, so far. As a heavier rider, I've loaded up the bike with about as much overall weight as you're looking to do. I'd highly recommend them.

Got them on Ebay through a vendor named Storm Mountain Cyclery. (Though, there are several vendors on EB that create wheelsets of this same sort.)

I'm much impressed by the Velocity Dyad for up to about 300lbs total load (bike + rider + gear), over city streets and less-improved roadways.

Examples:

• Velocity Dyad Shimano T670-S 36 Hole Touring-Commuting Wheelset Black @ Ebay -- $238 + shpg.
• Velocity A23 Shimano 105 5800 36h Gravel Road Cyclocross Bike Wheelset Wheels @ Ebay -- $259 + shpg.