...and I was so happy to find a 2-slot VX to pair with those oddball 16-chip 32MiB modules...
But, they're still an officially good match. And I experienced problems with these VX-density modules and later chipsets anyway. My stockpile mostly consists of BX-friendly modules but kept "TX grade" (may be a 'misnomer' as you wrote i430TX may accept BX-grade densities - but it can't cache them so I'm better off with not going over 64MiB) and, as you can see, "VX grade" ones too, just to be prepared for anything.
And there are chipsets from other manufacturers, too, there may be many anomalies... I've even seen a 5ALI61 POSTing with a 1GiB module, detecting the whole size and even booting up with it (DOS only, sorry, so it was entirely pointless) - but I wouldn't trust this combo with my life. It's way outside of its cacheability limits too.
Shame on us, doomed from the start
May God have mercy on our dirty little hearts