That trail picture is nothing. Well, actually it looks like a nice place to ride but if that's as bad as it gets then just a thicker road or touring tire would do you fine. I wouldn't think twice about running my 700x23 tires on there (well, my rear end probably wouldn't be happy due to the lack of cushion but I doubt the tires would care much). And any decent wheel will get you through that without problem.
My '03 Fuji cross has an Ultegra/Open Pro on the rear and the original Ritchey OCR on the front. I relaced the front last fall on my own and tensioned it by hand and trued it using the brake pads as guides. I then took it out for 12-15 miles on mountain bike trails (easy stuff for a full suspension mountain bike but still full of mud, gravel, some log crossings, ditches, roots, etc.). Both wheels were just fine. I've got Ritchey Crossmax 700x32 tires. I would have liked more grip on some of the muddy uphill grades but other than that it works great.
If you are considering getting new wheels for the road, then get the best you can afford and use the original wheels with fat tires for the trails. Or, just use the wheels you've got and see how they do. I think that most wheels other than super-light high-end road race wheels are much stronger than you expect. A hub, spokes, rim and tire do a great job of distributing forces as long as they are set up well. Just look at those old movies of Model T Fords rumbling over primitive roads with wooden spoke wheels.