Go to your local bike shops and see if they have any 2012 models left. I just picked up a Trek Cobia a couple weeks ago for the upper end of your price range.
That's my next step. The next week or two are going to be hectic but as soon as I can get the time I'll go to some local shops..
I'm 300 and was around 280 when in "good shape". Everything will cost more for you. On my 26" Santa Cruz Chameleon I ran 36-spoke Sun Rhino Lites in the rear, 32-spoke from. (in the background, first pic) Aluminum hardtails are your frame of choice. Thomson seat posts are the strongest, lightest available. As far as a 29er, I picked up this 600$ SE Cruiser for light duty. I'm pretty sure the components would not hold up to much more than mild dirt roads/street. For a 29er I would have built a set of 36-spoke Sun rims (or similar, mine were built 15 years ago) most companies make a double-walled rim. Good luck!
As a Clydesdale with tree trunk thighs and a bomber mentality, I agree you should ignore most of the 'you'll crush any wheel' hysteria. I'm 280 lbs and have brought my all mountain bike (giant reign) up chairlifts with a Moto helmet and pressure suit. Hav never pancaked a wheel - that goes for my specialized rockhopper as well. Ride them out of true? Sure! But never pancaked or had to upgrade wheels. I'd follow the advice others have offered; buy something you love and ride the shit out of it; try to avoid the big/square edge hits if you can but enjoy it regardless. The end.
See if there's any GT Peace 9'rs in your area. Back in New Orleans one of the LBS had one for $800 but that's on the high side for that bike. Probably one of the few 29'rs in your price range. (The KHS 650b was right at $900 new for a model year old last year!) (not gonna work for you as they only have S, but give you an idea of the bike build) http://www.bikesdirect.com/products/gt/gt_peace9er_multi.htm I think the wheel situation has a lot to do with how you ride. I've bent 26" XC wheels at 225#-240# BUT that's only when leaving the ground and usually landing to flat. I still think 29'r wheels will bend more easily than 26'r wheels at the same given rider weight. "Trail" is used loosely too, if you're looking at dirt paths then you probably won't have to worry too much about bending a wheel.
Kona Mahuna's are pretty burly. I sold one last year to my cousin who is 6'5" and 270#, he has had no issues other than a couple flat tires from riding in New Mexico. Any bike you buy in the price range you are looking at will be fine. The higher end bikes will have weaker wheels as they try to make them too light for your weight.
As far as the 29er versus 26er..... There really isn't any major difference for someone riding around casually. And arguably no difference for people that aren't, just a matter of catering to your weakness/strengths and the terrain you ride. Price point for a 26er is lower, especially used as the demand for a hardtail is very low right now and there is significant supply with many people (especially around the GTA) converting to 29er. Similarly old stock in a shop is likely high priority to have removed as few, if any people are buying new HT 26ers (around here). I won't predict where the trend is going, if 650b (27.5) will become the new standard, but 29er currently is, though 26er will never die. That makes things like selling if you need a little easier. Personally for tooling around on varied surfaces, I think the 29er is nicer (though again you probably won't notice a huge difference if casually riding). The big wheels do roll better, especially once up to speed, carrying better momentum. But whatever, if you are just looking for a bike to ride, get some exercise, I say get the best deal you can (26/29/650b unlikely) and ride the snot out of it. If you end up really getting into it, where you feel different equipment will make a difference, you'll be upgrading anyway.
http://www.walmart.com/ip/26-Mongoo...8013784367707&veh=aff&wmlspartner=lw9MynSeamY I want one. But seriously, I've got a Raleigh XXIX, 2009 model that was pretty much new, picked it up from a guy on craigslist for ~$300 in April. Love the thing. Complements my geared 26er well.
A buddy just got this: REAL NICE. One of the Neater features is the seat that goes up and down with the quick release lever on the bars... Great idea for getting it out of the way when yer standing up and letting the bike move under you...
Whatever, they don't make that much, I've turned down more than one offer for a GS position...half because of money, and half because of travel. If I wanted to pull +60% travel I would have just stayed in the military.
If you go with a bike with Easton Wheels, recommend you have spare spokes ON HAND! I have a Kona King Kahuna and I popped spokes a couple of times, finding replacement spokes was impossible locally. That sucks when you're on a 10 day vacation in Garmisch and the Black Forest, I should have figured that out when I lost one at home.....
For a rigid bike I love my Surly Karate Monkey. The complete bikes are single speed though. It will accept gears, but you will need a different rear hub. This bike doesn't care if it has a suspension fork or rigid, rides the same either way. And most rigid 29ers are single speed.
I imagine there are a few hardcores that would ride a fixie onto the trail, but generally you'll find a freewheeling hub.
Okay - "fixie" means fixed hub so pedals have to move if rear wheel's moving...freewheeling means like the old single speed bikes I rode as a kid: you can "coast"...that about right?