Try these, I'm 220 lbs dressed:

Vuelta Corsa HD Road Wheelset

I've got two sets (on different bicycles) and haven't had a problem with them. Neither pair needed to be trued or have the hubs adjusted, I simply put them on my bicycles right out of the box. They're a little heavier than most other wheels, but if you're 350lbs what does an extra pound matter? And they are inexpensive. Even if you want to get lighter wheels in the future, you could use these for daily rides so the newer, lighter wheels don't get screwed up. Also bought a pair of Vuelta's single speed wheels for a SS project, and they're holding up great, too.