I like the decal idea by AJ as well. As far as parts go here's my list;
1) 10 hole chrome wheels from the Kenworth K100 Aerodyne kit
2) Front six spoked wheels and tires from the Autocar dumptruck kit
3) Rear air ride suspension from the International 4070A kit.
4) Rear suspension and axle from the Ford Louisville Delivery Truck kit.
5) Six spoked wheels from the Volvo N10 tractor kit.
Brent, There are no kits of the 110"or 120" sleepers for model trucks. There are no aftermarket model builders making them either that I know of. The best thing you could do is scratch build one yourself. You can do this by using .020" or .030" sheet styrene.
George, Great work on scratchbuilding the cab. Don't know if you know this but, you can buy a resin cab conversion in 1/25th scale of the Mack B-61 from American Industrial Truck Models. Here is a link to theri site. http://www.aitruckmodels.com/
Wow, this is a great topic. The worst part of building for me would have to be painting the cabs, hoods, sleepers, etc. "bodies". I'll get the body work all done, sanded real nice, everything is straight, and just the way I want it, then I'll shoot some paint on it and it will not come out the way I expected it to. Orange peel is the biggest thing to try and avoid when painting. I have gotten better over the years, with all the tips and tricks I've learned from friends. I've had cabs/hoods not come out right the first time and strip them and repaint them 2 or 3 times before I got it right! Ahh! It's just like anything else though, the more you do it the better you will be at it.
You can try these two companies. American Industrial Truck Models and IIIini Replica Conversions
Here are the link. http://www.aitruckmodels.com/. The link for Illini Replica conversions is on the front page of American Industrial Truck Models at the bottom right. AITM is great to deal with and the castings and service is great. I have never dealt with Illini before, maybe somebody here has.