If you haven't already you should check out some of the wheel posts on the Clydesdales/Athenas forum. We larger folks quickly find out that wheels are the weak point of most any bicycle.
While going to 36 spoke wheels will get you about a 12% increase in wheel strength, all other factors being equal, nothing is as important as proper tensioning of the spokes.
Spokes will most often break at the bend because of insufficient tension allowing them to flex repeatedly. Any metal which is bent back and forth will eventually break.
Custom built wheels will help, learning to true and tension your own wheels is a good idea too.