"I've been keeping an eye out for cheap solid state amps but the only ones that are that cheap, go pretty fast"
Are you looking for >>dead<< ones? It would surprise me to find that every music store on the planet does not have at least one unfixable corpse lying around. I mean, think about a 1x12" 40-watt SS combo amp. You can buy such a thing new for well under $200. You can buy such a thing used for $125, as many as will fit in your truck. One that needs repair (assuming blown output section) needs minimally $20 in parts and minimally an hour in labor, more likely 2 hours, more likely $50 in parts by the time they order the stuff. So if a little music store has one of these things, it will cost them roughly $100 just to see if they can get it working, which they usually can't, only to try to sell it for what, $175? $125? In my estimation they almost cannot touch it. Make a call to some local Mom & Pop music stores.
A while ago I bought a used excellent condition Fender Deluxe 65 (working) at a store for $110. It has a Celestion speaker. I quickly managed to blow it up futzing around with it. So what do I have? A clean, entirely Fender-looking cabinet, a $40 (?) Celestion speaker, tolexed, handle, corners. The chassis is angled so it won't be that easy to tubify it, but it can be done. Peaveys are a little better, probably more robust cabinet, too. There are bazillions of these things out there, many of them dead!
Alternatively if someone has such a thing, it is sitting in the garage and 2 people have told them "it's not worth fixing." Offer $20 and let them keep the speaker. I think if you placed a Craigslist ad you'd have 10 people call you.