boy&hisdogs
I'm Awesome
In retrospect, this is probably the wrong category for this thread, since I'm neither planning to lift the vehicle nor drive it offroad, but I couldn't find an appropriate category in the Street section
Honestly you're probably in the right spot, I think the offroad guys are more commonly looking to swap to bigger axles/front ends since we use bigger tires that break 1/2 ton stuff, especially since your truck is 4x4. It sounds like a cool build though, especially with the NP149. It's easy to find the 6 lug SF with 3.73s and a G80 though, and just as easy to find a matching 8.25 in the pick-and-pull type yards. It's a direct swap too, all you need is a conversion U joint. I know the SUV's used shorter overall length springs but I think the mounts are the same as the pickups and should bolt right up with anything but a dually axle.
The big chain yards that use flat-rate pricing (here the Pick-N-Pulls just call it a "truck axle" doesn't matter if it's a 10 bolt or a D60) are the best place to go since you can save a ton of money vs someone who knows what they have. That way you won't be out TOO much money vs using the one you already have. I think it's a worthwhile swap just for the big brakes alone, especially in a Suburban full of kids.