Sorry all for the horribly late response, I must've been sidetracked and then forgot about this thread. Dad got a kick out of quite a few of the responses, and he definitely appreciates them all.
MarkV: You're right, this wasn't his first rodeo, he loved that phrase btw. I believe one of his first was building a homemade off-road, I dunno, "fun vehicle". Kind of similar to say a side-by-side off roader but built heavier and quite a bit bigger but only 2WD. That got completed, and eventually cannibalized for something else. Now its sitting derelict. Then came a further evolution of that he did for a handicapped man (paralyzed from the chest down I believe). Not too sure what it was powered by, but it had a hydrostatic transmission, a folding rear ramp, a locking system to lock his wheel chair in place, and quite a few different unique items. The best way I can describe it to you is in his own words, it looked like a WW2 halftrack in the way the grille and hood was laid out.
CCWKen: Dad liked that image. He was particularly impressed with the reach of the loader. A very sharp machine for sure.
Woodlandfarms: Yes, he still has it. Uses it often in fact. Well especially moreso this year with the additional snow in its primary role of snowblowing (and using a blade).
Spudland Dave and Bill Barrett: He used Case hydraulic drive garden tractor rear ends. If you have any other questions feel free to ask, he'd be happy to answer.