Yes it is possible. A 6 window, to 8 window shorty, full size, not van cutaway, dog nose would make a nice tow rig. Good stable platform that will handle well. Thing is most buses this size have smaller engines and the AT 545 trans. Not so good for towing. If you look at newer buses early 2000's up to 2004( after 2004 you get more emissions stuff starting with EGR in 05) you can find ones with the Allison 2000 series trans, in rare cases the 3060. Both are better choices for towing. Or a manual trans. The DT466 can be found in short buses, and would be a nice engine for towing. I also like the Mercedes 906
By the way I have pushed the limit pretty good with the old International and towed up to 18,000 lbs. 5 speed with 2 speed rear. Gas engine. Just changed the engine though....
My Thomas I have not gone over 10,000 lbs, and do not want to push it to the limit, so staying 10,000 and under on it.