That's too bad if they can't be refurbed as survivors but good on you for even investigating it and not directly abandoning the notion.
If it shakes-out that way, here are my ideas:
1) Beg Wayne for 3-pi thermionic design. Do quickie qtr-wave sims using ewave woofer data. If no showstoppers, whack new baffle to put driver and port where he had them. Stick ewave guts in new baffle. Don't push a bunch of watts but just test-listen (and see how much "bigger" your ewave can sound). Worst case, put your ewave guts back where they were, out one pair of baffle's work but prepped for re-baffling.
2) Beg Wayne for ancient 4-pi thermionic design Obtain remaining parts and make new baffles.
3) Lots of other stuff...depending on what you want. 5+ ft3 is a nice cab to have. And it's built Well I really like those cabs. Heck--I'll do the sims if somebody tells me where the old designs had driver and port relative to overall cab dims (is that a dc300?).
Thanks for sharing the great stuff. Good luck and keep us posted.