I am sure sorry to hear about your challenging situation, loopee! It has been an honor to have a pair of my cabs in your home, and I understand if that's no longer practical.
The Thundertots were one of a kind (okay, two of a kind) and loopee has the only two. They were named by loopee herself, and isn't that a great name?? She asked me for lightweight basic cabs that would handle a lot of power. The single 12" woofer in them is a custom job that uses the Kappalite motor, 8 ohms as I recall and rated at 450 watts like the stock 3012LF, and I don't have any more of them.
I don't remember the dimensions but the box was just about as small as I could make it and still shoehorn in a 12" woofer and a rear-facing port, so the footprint is probably about the same as a Hathor 1203 but they look shorter than the 1203 in the photo so they probably have even less internal volume. My recollection is that they weighed about 23 pounds each.
Well, I hadn't been planning on doing a production version of the Tots, and of course I'd have to get loopee's permission to use the name. Theoretically I could use the 4-ohm Kappalite 3012LF (same as what's in the TC112v3) and include the "4/8 ohm" switch so that it could safely be paired with an 8-ohm cab, such as your TC112v3. Not that I don't have too many projects going on already... but Tots at least would be pretty straightforward.