James, don't take this the wrong way, but you like those things? Usually I agree with you, but I find those to be the speakers that give Celestions a bad name. Ever tried the Classic Leads (knowing you, probably :))? They have good lows too but not as muddy and smoother (and more) mids... I replaced the G12T-75s in my slanted cabinet (the only one I ever really use) with Classic Leads and I've only used my straight cabinet two times since, once when I first got the Classic Leads for comparison purposes, and the other time was actually when I was making Les Paul + Rebel Yell clips I decided to see how they sound through that.
That said, I have a near perfect condition JCM 800 era 4x12 1960B I'd like to get rid of with four original G12T-75s.
Avatarspeakers.com sells empty cabinets as well, but I'm not sure if it will be any different than a Marshall 1922. Is the 1922 the budget 2x12 and the 1936 the good cabinet? Is that how it works? I've never even seen a 1922, and I don't think you can buy them in the US.