I just looked up the payload on a 2008 Xterra and it ranges from just under 1k to just over 1k. The just over 1k is most likely for the 2wd models. Every option added will subtract from the payload, so that will probably be your limiting factor.
That being said, there are plenty of shorter trailers out there right around 3500# gross. We're looking to trade up from a Starcraft 17' that we've had for 6 years and never gave us any problems. We towed if all over the east coast with a 6 cylinder SUV with no problems. Had a little more payload than the Xterra but otherwise very similar.
Don't get discouraged, you don't need a condo on wheels, so you should be able to find something.
When looking used, consider a private sale, but talk to the seller to get a feel for what kind if maintenance they've done. All tt's require preventive maintenance and, if not done, could lead to leaks, bearing failures, etc. if no pm was done, unless it's close to brand new, I'd walk away.