The 8.75 Chrysler axle was a good setup. Drop out 3rd member like the 9" Ford, 31 spline axles. Dodge put them behind everything except the Hemi
If you want to build a totally custom axle and keep it "in house", the 8.75 has a few things going for it, and like the 9" a few things to avoid.
It has a welded-up sheet metal housing, and can be trussed as easily as the ford. Down side is, it wasn't used in the pickups, so there are no heavy-wall tubes: It HAS to be trussed to strengthen it. On the up side, the pinion doesn't hang as low as the 9", which gives the drive shaft a little more clearance. The 3rd member is physically smaller, weighs less, and doesn't hand down as far. It can be cut/shaved just like the Ford. Massive ammount of aftermarket parts available for it, mainly for drag racing. Gears/spools/ Detroit locker/trutrac available. as well as high strength axles. There was even stock versions with the 5 x 4.5' bolt pattern(look under a Duster/early Barracuda in the junk yards) although you probably want to start with a bare housing out of a mid-70s Polara/New Yorker/Fury to get the toughest housing available,...
Down side: No ARB/OX/ected/electrac,... or any other selectable locker. I don't even think they make drop-in lockers for it. Might be wrong there. 'You'd have to research it.
EDIT: The biggest advantage to either the Cry. 8.75" or the Ford 9" over the "conventional" axles is massively lower weight.