Possibly a little smaller than you're looking for but we have a 16' Scamp with flush john, shower and tanks and really like it. Sleeps two comfortably and two more in a pinch. With genset and all our gear it weighs in a bit less than 3K. There's a picture of it in the generator thread of the small trailer forum.
The 17 ft. Casita might also fit the bill. Another molded fiber glass trailer. It is made in a couple of different floor plans, offering different bed arrangements from true king, queen, twins, true full size, or true full and a twin. It has a bathroom and can be had with a larger water tank to accommodate some boondocking. They also come in 16 ft. and 13 ft., both can be had with a bathroom. Terry
Also the Oliver trailer...17 ft fiberglass, GVWR 3500#, full marine bath/shower, holding tanks, bed, table. Has everything you need and very lightweight.
JJ & Sandie
Li'l Jack and Pickles, chihuahuas...Chewy, poodle 6/15/95-7/4/08 We will always love you Chooch.
2003 Chevy 2500HD,LT,CC,SB,4x4,Duramax/Allison
2007 Starcraft Homestead 262RKS
We boondock a lot in our 18' Pioneer. 3600 lbs dry with dual 30 lb propane tanks and dual Trojan batteries and an air conditioner. I weighed the trailer full of water, propane, food, and our normal camping stuff, and we were pulling 5400 lbs. Plus I had another 275lbs in the bed of the truck. I like our tt a lot, but for boondocking, the lighter the better. And another thing to consider is your clearance to the ground. Our Pioneer has a high stance which is good for going off paved roads. But it is quite high so probably cuts through the air on the highway like a 8'X10' brick. Many have pros and cons. You just have to weigh them all out and pick what fits your bill the best.
06 F-150 Lariat 4X4, 5.4, 3.73 rear. Reese WD, and sway. Pulling,
06 Pioneer, 180CK, with air.
Just sold a Jayco Kiwi 17A, it had all you are asking for and had room for 4 of us. The fold out beds give it more room than a regular 17 footer. Easy pull, I can't remember the exact weight but it was under 3000. I enjoyed it, but after a large 5er, got too small for the DW, at our age, we needed a little more room and space for the grandkids. So went to a 25 footer ultra light, its 3790 empty, 5500 GVW. Trail Cruiser 23SB by R-Vision.
The Casita and Scamp are more rugged than the Fun Finder, but we just finished a really fun trip to the Grand Canyon in the Fun Finder, and it did just fine during a week of pretty serious boondocking -- rough dirt roads and some gentle off-roading. If you have a fast connection and a few minutes, check out the pictures of our little Fun Finder having the time of its life:
Having said that, though, a "stick built" ultralight (like mine) is hardly the best rig for major boondocking. The fiberglass Eggs are way more durable. But my Fun Finder has 6'3" of headroom, and that is exactly how tall I am. So that is why we did not get a Casita.