I'm not an expert at towing by any means, but I have a 1997 Jeep Grand Cherokee 5.2l - It is rated to tow 6500lbs in the U.S and 3500kg (7700lbs) in the UK - I have used it to tow an enclosed 16*7 haulmark trailer several times and it has done a decent job at it. I intend to use it next year to tow my civic in the haulmark trailer - for a combined weight around 5500-6000lbs. I've also seen them pulling large caravans (20-24ft) before.
With it, I use a Tekonsha P3 Brake controller, a load distributing hitch, and a larger setrab transmission oil cooler.
I don't tow past 60-65 mph - I get 10-14mpg towing flat, and around 9 in the hills.
They run under $5k now and can go as low as $1000. In terms of parts, my motor has 160k miles on it, I swapped in a 242 transfer case, which gives me 2wd/4wd pt/4wd full time/4lo options. Even though the transmissin is still doing OK, my next upgrade will likely be a rebuilt transmission with uprated clutch packs/torque converter.
I'm not saying it's great to tow, but it's a nice DD and it has done a decent job every time i've towed with it so far.
I guess the key for me is to keep the speed down, and use a good trailer brake and weight distribution setup.
In terms of other jeeps, there is also the 1998 5.9ltd, and the 2001-2004 4.7ho motors. If i were to replace mine with another SUV, I would consider the 2005+ Trailblazer with the 5.3 v8 motor (MDS), The 2005+hemi (MDS) Jeeps, the 2005+ CRD (Diesel) jeeps, but those run around $15-20K Used.