I weight around 330lbs, and the used rear wheel from hell's rim bent out on one side. I was looking as some sun rhyno lite rims as a replacement and have a couple questions.

1) is 32 spokes enough? I'd like to reuse the hub I overhauled 2 months ago.
2) if I should rather go up to 6 spokes, what's a good but not break the bank hub? I've read that the shimano xt would fit the bill. Any recommendations? Looking to keep the 8 gears in back.
3) This will be my first wheel build. Was looking at double butted or straight gauge. Seems that the db spokes are stronger, but harder to build with. How hard or how much stronger?

The key with wheels is not the spoke count, but how well the wheel is tensioned, if the spoke tension is too low it will break spokes, even if there are 400 spokes on the wheel. One of the things you want then is a spoke tension meter and a rim where the maximum spoke tension is published, you tension all spokes to that level and then true by loosening so that when your done you have the highest tension possible in that wheel. As for the hub, most hubs are replaced not because they need to be, but because a pre-built machine laced wheel is so cheap that by the time you buy rim and spokes it cost's as much of not more then a pre-built wheel laced in China or some other far off land. There is no reason a hub can't run 100,000 miles, if properly maintained.

I work for a company that uses heavy steel plates in its construction. I've been tempted to cut a 1-spoke wheel from 1.5" thick plate and then have it machined to fit a tire just to prove it can be done.

Anyway, from an engineering standpoint, the performance of a wheel is not controlled by number of spokes or rim type or proper tension or lacing pattern or hub details or spoke size or type, but rather by a combination of all those factors. If you're on the upper end of the weight scale and having problems, it would make sense to upgrade somewhat in each aspect, but there's not any one factor that's going to be a magic fix.

To give you an idea- on my Raleigh Sojourn, the rear rim gave out after about 4400 miles. It was a 32-spoke rim. Raleigh sent out a whole new wheel, of a different style, which I think the bike store guy said was used on one of their commuter bikes. Anyway, that was a 36-spoke wheel rather than 32 spokes, so in that respect, it was an upgrade. That wheel lasted 500 miles. So just the spoke count by itself wasn't much of an indicator. And that was with me at 220-240 lbs, by the way.

A while back, I was at a bike rally, and a couple there on a tandem had low-spoke-count wheels. I think the guy said they were Shimano "Sweet 16" wheels or something of the sort. He looked to be maybe 200 lbs, wife maybe 140 or so- neither was "large", but still, combined, they were putting a fair bit of load on that wheel and seemed to be doing okay. And then a while back I was at a bike shop, and they had a tandem in for service that had 48-spoke rims, which I didn't know existed (evidently, they're a tandem-specific thing). From what they said, that couple had had a lot of wheel problems in the past, and those wheels were their ultimate solution to the issue.