I went back to the store, y’know, just to see if either someone else had bought it or if it had been marked down even further. Just my luck, it was still there and marked down a 2nd time (to $89.00). 
So I bought it. 
It’s the “deep” version of A-C’s 6qt sauté, with a smaller diameter floor (10-1/2" instead of 13") and taller sides (3-3/4" instead of 2-1/2"). The diameter matches my 3qt sauté and 8qt stock pot, and the wall height fits right in-between those two. I will say that there have been a couple of times where I wished my 3qt’s walls were taller while my 8qt’s walls have been too tall (for convenience).
For anyone interested (Chem?), the D5’s pour lip measures 0.020" thicker than my pre-D3 A-C tri-ply 3qt sauté, and that appears to be the middle SS layer’s addition (that is, there’s no more or no less aluminum compared to the older pan).
Here’s a link to the pan at W-S:
https://www.williams-sonoma.com/products/all-clad-d5-brushed-stainless-steel-6-quart-deep-saute-pan/
