Someone had posted one in the Heavy Haulers section here, a C60 on a 88-98 C3500HD frame. That swap seems perfect in my mind, gets the truck down much lower than it was, and 5/10 lug axles so your Alcoas should bolt up as is (I could be wrong there). Plus still has a 15000GVW so using it for towing and hauling is still an option.
http://67-72chevytrucks.com/vboard/s...07&postcount=4