Is there a JunkYard thread yet?

Lincoln MK7/Continental rotors will convert the front to 5-lug (and they also use the SVO rear disc setup, and most use the SVO aluminum MC).

A 4X4 Ranger rear end will get you decent gears in a 31spline 8,8" chunk, and a pair of drivers' side axles will convert a Foxbody 8.8 housing to 5-lug.

Areostars use the same rear as a ranger, but most are open units with crappy gears (and porbably 28 spline). Note that a majority of Rangers/Areostars use the wider 2" wide drum setup also.

Mk7/Continental chunks are usually posi, but the gears may suck, and I'd guess they're 28 spline (too lazy to go look )

Somewhere on the net are measurements of Ranger short-side axles, so you could check the length of the unknown ones you found.

A visual ID tip: Ranger/Areostar rears are a little over 57" axle flange to flange and one side is visibly a lot shorter than the other.

For other upgradable items from other FML's, Jrichker has a post with that info (TC rear ends, SN95 TB's, etc).

Good luck.