3.73's were the L05 V4P towing gear in the 8.5". That towing package was revised to 3.42's for 94-96. With 8.5" gear still.
(Wow... 2000th post.... I spend too much time here!)
I did look up limo axle, it was there, but very few available. Did the limo have the ABS? I am pretty sure TC was not available on the limo.
I just put a 9.5" in my Suburban replacing a damaged 8.5" (ran it low in gear oil and didn't know it till it was too late), and I can definately NOT recommend it if you want weight savings! That sucker is HEAVY over the 8.5". I am guessing 75-100 lbs over the 8.5". The case is heavier and the tubes, everything is beefier. Worthy in the truck, but not likely worth much in a car unless you are seriously towing or drag racing (well, may be worth it when you stick on them 42in tires...)