I have a chance to buy a Marshall B cab for very short money. Correct me if I am wrong but isn't the 8412 a smaller import cab that will not fit correctly under my JCM 900 slant?
GC every once in a while will have them for $100. Celestion loaded and real plywood makes them a killer cab. They're nice, tight and punchy. Build a rack to run on top of the cab and place the head on top. Problem solved.
I was talking about a rack case complete with rack effects, more preamps, EQ's and multiple power amps. Nothing that would really do anything for the sound, but would look badass.
I do not consider myself OCD but having a bottom cab even a 1/2 inch smaller than the top cab would drive me crazy. The same thing with heads, if it is wider than the cab I twitch and blink.