[hcoles]

Are you tensioning the spokes too high? Did they pull out on the gear side?
I don't have to tell you tighter spokes do not make a stiffer wheel.
Some wheels may have more meat at the spoke holes but I don't know what make/model to recommend. You could try Merlincycles.com, I get stuff from them off and on - free shipping probably for wheels. They also have a USA site. I use BikeHubStore for hubs, spokes and nipples/etc. If you get a different wheel you may need different length spokes. The new wheel(s) should include the ERD - then you can order the correct length spokes.