A minitruck rear end will get you up and running quick and cheap. Brakes are better than stock cruiser stuff too IMO... I had one in my crusier for a year before doing my cruiser/mini hybred centerd rear end that went in when I back-halfed and linked the rear suspension.
Search for my buildup over on pirate4x4.com. Its in the sticky at the top of the page in the LC secton under "all the buildup threads"
If I had alot of money Id do a TrueHi9 in the back of mine.
Other options are standard 9", early cruiser, custom 60 or 14bolt, etc...
Chris