Chuck and cheese re tearout fix with tape: yes, an excellent and should-have-been-obvious-to-me tip on the tape. Will likely try it next time around. Also, cheese, I like those under bed drawers a lot.
afish re tearout fix via CA glue: CA glue is a really interesting idea. Wondering if a dollop of hot glue to plunge into, then pop it off would work? Regardless, that seems more onerous than tape or a sacrificial block, but still like the concept.
Packard re Blum Tandembox: Having never lifted such a drawer on my own, I honestly had no idea how much they weigh. I can't find a weight on the Blum brochure either. I have to say I don't love the half height sides (something I was already considering with normal materials) and look. But likely will look into more just to see.
Svar re Premcore: I have inquired about similar near me with little luck. I have not inquired by that name, and will try.
Packard re Air Streams and foam/alu panels: you have touched on (eventually) the underlying motive—these are destined to be in a tenement on wheels (RV). The aluminum panels are indeed NASA worthy, but possibly beyond my humble abilities to source and work in a way that looks presentable. Still like the concept, as that type of off the wall things is indeed what I asked you all for.
Tsmi: I will say that my (limited) experience with the 9mm boxes really surprised me with their rigidity if tightly constructed. After the project, it made me think I overbuild much.
Packard and Chuck re triangular braces: I think this is my favorite idea of the lot. It might have a funny look on the inside of a drawer, but the strength, repeatability, and ease of assembly if I go really thin on the ply seems unbeatable. I may try a mockup of this.
Crazy re underside support: Although 30” wide, it is still only 15” deep. My thought is it’s more about the shortest distance getting too great for the ply. Although at 15”, 6mm is going to sag, and your fix is both quick to do and not (that) heavy. Will likely try a version of this (see below). I'm wondering if poplar can be improved upon for optimal rigidity vs. weight for a 1/2" strip. Likely only on the margins I would imagine.
Packard re single dovetail for underside support: wondering why the toil for a dovetail for such an attachment, other than several decades of feeling good (which, on net, was probably a serious good return on that time investment). Would my life be better or worse if I used mechanical fasteners or glued it solid?
ALL: Thanks for the inspired and entertaining responses. A fun first round wondering around here in the FOG. I hesitate to even raise it, but bonus points to anyone with drawer slide divine inspiration while I go do some mockups to test the above.