I shopped very diligently for an LBZ a few months ago, but couldn't find a clean one for a price I was willing to pay. I'll outline what I bought to give you an idea what you might find if you look diligently, as I did.
I bought a 2004.5 Ram CCSB 4x4 5.9L Cummins. It was a one owner, fully loaded, new truck trade in, Arizona no rust truck, with clean carfax and had 137K on the clock. I got maintenance records with it. The previous owner towed a fifth wheel with it. It has several professionally done mods, including an exhaust brake, a free flowing exhaust, and a tuner with gauges that is adjustable on the fly. The new truck dealer I bought it from did the brakes all the way around, put in all new front end parts, rebuilt the AC compressor, changed the fluids, etc.
I paid $18K for this truck, and after several months of use, including quite a bit of towing, it has turned out to be extremely reliable and gets good mileage. I tow a 7500 lb TT (actual weight) with it, but with the capacity of this truck, I could upgrade to a larger and heavier trailer, even a fifth wheel, if need be.
When shopping, I wanted a diesel, but was willing to buy a 3/4 ton gasser if I found a clean one for the right price. I'm glad I got the diesel -- it tows like a dream. I also feel that whenever I want to sell it, my resale will be much better than if I had bought a gasser. Since this is one of the last generation of pre emission diesels, I feel that if I want to sell it when it is 15 or 20 years old, the resale will likely be much higher than the resale of a gasser of similar age.
One of the things that I did not like about the LBZ was that the fuel tank is only 26 gallons, whereas mine is 34 or 35, plus the previous owner did the commonly and easily done fuel tank vent mod, so I have almost a 40 gallon capacity without having to buy an extra auxiliary tank, which I did not want to do -- didn't want the expense, and didn't want the aux tank taking up valuable bed space.
You might also shop 7.3L Ford diesel trucks. I also shopped those when I was looking. Just throwing out some things to think about. Best of luck to you!