Does the 3,000 lb estimate include a full load of gear, water, batteries. propane & fuel? If so I suspect it is not as far off as we might initially expect. Advertised weights for many trailers (off road or not) don't seem to agree with highway scales very often and gear/water/fuel/etc. along with off road prep adds up quickly. Our 2004 double cab Tacoma supposedly weighed about 3,800 pounds empty and dry off the production line. Moderately outfitted (bumpers, winch, shell, dual batteries, larger tires, solar panels, fridge, etc.) and loaded with fuel, water, food, camping gear and Magolina for a three week trip she was at 5800 - a cool 2,000 pounds! I'd stick with your 3,000 lb estimate or wait until your trailer is built and get her weighed.
Unfortunately, towing capacities seem to have the opposite relationship with measured weights. All of the vehicles I've owned have had advertised towing capacities 1,000 to 3,000 pounds greater than what they efficiently towed in the real world (one exception was 2002 Subaru WRX wagon). I wouldn't want to regularly tow 3,000 pounds with our 2004 double cab Tacoma. I don't know about the 2nd generation version, but it might be slightly heavy for them as a regular tow. Bjowett's suggestion of a Landcruiser sounds good. A first generation Sequoia might also work?
Howard