Rearend options

Yep....people selling those stock 8 3/4's are smokin' crack usually. I could see if someone needed a bone stock A body rear end for some insane reason...then demand dictates the suppliers asking price. I suppose some people think their stock A body 8 3/4's are made out of " Inobtanium " But a cut down B body deal would work fine and if narrowed correctly, would no doubt be straighter than a stock housing.
Plus you would have a set of large drum brakes all set for the 4 1/2 bolt circle on the axles you would have to order.
The axles are around 250 - 300 bucks, and you could set them up with whatever style bearings you want.depending on the cost of the B body axle set up you could end up cheaper than the stock used A body 8 3/4 and have all new parts except for the center section.
I never have liked 8 1/4's....the damn fill plug always leaks ;D

I have had 8 1/4 in two dusters - one in a 400hp small block and one in a 400hp big block - both have lasted a long time and not given me any trouble. Even the $200 posi's i got have lasted great and always spin two tires. I just used them because thats what I had and I didnt want to spend the money at the time for an 8 3/4

AAOUTLAW said it well. I have a spare a-body housing in the garage, but I also have a c-body housing that will likely get cut down in the future. The brakes are already being used, though so I'll still have to get another set.

check out my post for an 8-3/4 on Ebay.
It may work for your application depending on what you're after.
Later
Dart 440 4spd

i bought my housing off ebay for $250. the guy builds them all the time (great feedback). mine was cut down to the desired length. very nice guy to deal with. he calls you to make sure what you really want. im filling my 8 3/4 with all new parts. i have moser axles (which i had the guy who bulit my housing order) and will later get an alunimum 742 case from dts, detroit locker true track diff, moser ring and pinion, and disc brake set up (havent decide what brand of brake). im taking my time with my car so i can get what i want the first time round. id kinda like some sorta 4 link system, but to be honest i really could just go with leafs. art marrison has something called a 4bar that someone installed on their 70 challenger 8 3/4. im just exploring my options.