[yossarian19]

If you are swapping rear ends AND doing front brakes, yes, it's totally simple to go 5 lug. You can find front brake + hub kits in 5 x 4.75 pretty easily and of course that's what most GM rear ends are going to be.

I kept it 6-lug so I could defer the cost of wheels / tires and because I just thought a 6x5.5 truck was cooler than a 5x4.75 truck but that's just me.

I think anything "Tahoe" or, really, model year 1988+ is going to be a bit wide. You could do it with the right wheels I think but then you're back to limiting options.

A good six lug donor is the Jeep Wagoneer Dana 44. The AMC 20 is also a good axle, again from a Wagoneer, but the Dana is your first choice. Easily available positraction parts, disc brake setups can be done, strong enough to fill the bed with sheet rock or tow something with it. Upgradeable to just-plain-silly degrees.
Another six lug option is any 4wd C10 or early enough I think the C10s came 2wd 6 lug, 12 bolt axles. I know less about them but they are a good axle.

Also, be aware, you can't get a posi for the stock 55.2 rear end but you can get everything else to rebuild it and even put disc brakes on it now.

In 5x5 pattern a Jeep Grand Cherokee from 99-04 is the right width, has good solid brakes on it, comes mostly in 3.73 ratio. Some came with a hydraulically driven limited slip. It's a red-headed stepchild of a Dana 44 with an aluminum center section, steel tubes, and IIRC a Dana 60 pinion diameter / bearing set. Not as easy to upgrade as a regular Dana but it's the right width, right ratio, it's available and it's got OEM discs.

You might also look at Isuzu Rodeo / honda passport rear ends. I think they may be a little narrower, like around 58", but they are a disc brake 6 lug Dana 44.

As for five lug options outside the Grand Cherokee... I think a Gen II Camaro fits, but somebody else will know a lot more. I kept it to 6 lug so that's what I know.