The rig I bought a about 2-1/2 weeks ago is an older 1989 Skyline Layton, 23' from ball to bumper. Per the PA title has a "unladen" weight of 3500 or 3800 and a GVW of 6,000. I think the unladen of 3500 is optomistic and it's probably closer to 4K empty.
I figure loaded up for camping (no water in the tanks), I'll be somehwere north of 4500, probably closer to 5K or so.
When I towed this rig home (empty, no contents), my 00' Expy Eddie Bauer (see my sig) pulled it just fine. Sure, on some of the grades I was into the throttle a little bit and I slowed down a little bit, but I was no-where near flat to the floor or anything like that.
I'm sure fully loaded with firewood in the back, all contents in the camper, food, and my wife and two boys it will work it harder. In fact if/when we make it to Knoebel's (hopefully in 2014!), I'm thinking about having my wife follow me with the boys in her car to keep some of the contents and weight out of the Expy. There are some SERISOULY long/steep grades getting to Knoebels, especially after you get off of I-81 and onto 54 and 487. I have a feeling I will be near flat to the floor pulling some of those, but we'll see.
At any rate, I know the Layton is older and heavier than some of the newer light and ultralight rigs for it's size. I had no sway issues going home with it, and it was even "nose high" which is not what you want to help reduce sway, but the Layton was really low to the ground (before I converted it to an over-slung set-up) and the reese hitch shank I got with the camper was already at it's lowest setting.
I agree with the other posters. In terms of length and weight, I would not want to tow any more than a 26' trailer (overall, ball to bumper) with my Expy. I think the Layton pretty much has it at it's limits, at least in my opinion.
YMMV,
Greg