No, no one has made a square body Burb in any scale, except for some random resin cast body conversions that were done years ago and are hard to find. It's not just taking a pickup kit and a blazer kit and mating them; I've seen a detailed writeup on a model done like that in Scale Auto Enthusiast magazine probably 20+ years ago. That's basically what this guy had done, and it was a nice model to look at....if you didn't know what a real Burb looked like!( If you read my signature, you'll see I have some experience with square body Burbs!) These trucks are where I really began to get my wrenching skills refined( thanks Dad!),and we went from bumper to bumper on all those trucks. Plus many in the 4 Houston area pick a part locations!
The only properly done 400 Burbs are the Brookfield 1/24 or 1/25 diecast ones. I don't personally have any of them, but many members do and have posted them on the GMT 400 memorabilia thread. Matchbox made a 97 Tahoe back in the late 90s, the last time it was out was around the mid aughts.
The Auto World square body trucks are great( except for the incorrect chassis plate, which is a 4x4 version with the solid axle). M2 also makes a nice one, with more chrome pieces. I'm hoping with the popularity of the GM SUVs, one of these companies will make a Suburban newer than the 64-66 one that Auto World has out. Greenlight has a new Tahoe in police specs; maybe they'll be first to do a Burb. Their square body trucks are really nice too, so they could do it justice.