Eddie,

Talk to Farrout. While his Tahoe/Yukon was not an XL he did tow his 20' enclosed for a short while with it.

You are also welcome to take mine on a test drive. 24' box but I have to tell you, I personally think that 20' is going to be the max for your chassis. Heck, even the trailex open, tools, and spares with my car was TOUGH on the Suburban I had before the Duramax. It would tow fine on the flats but don't count on making any time going up hills and heaven help you if you had to stop quickly (it only had surge brakes).

Call me if you want to try it out.

Paul