In 1969 I bought a used '67 Epiphone Rivoli and a Standel Artist XII for $225.00. I still have the Rivoli and see it on eBay for up to $2,000.00 or more (don't know if they ever get that). The Artist XII finally crapped out around 2006.
Used SWR, Fender (blackface), Eden, Carvin, Berhinger, Standel, Vox, I prefer Carvin and SWR but I also have an Avatar B212 with the Delta LF speakers. That, I will never give up.
Ah, yes, the Teneyck 550 crapper with the Christmas lights. I even installed blinking ones. MDF cabinet and crapola speakers. Weighed a ton. It did have it's own moving dolly that screwed onto the base with a wing nut. The cabinet wasn't ported so no low end. I tried putting Utah 15's in...
The MB210 would fit perfectly on top of an Avatar B112 cabinet and give you the low end better than another 210 cab IMHO. The way I see Carvin pricing their ext. cabs. would probably have a MB210E at about $300, just looking at the way the MB15E costs $249. Where you could pick up a BR210-8C...