The successor to the B22 is the B66, both are limited to 2 1/2" x 2 1/4".
Durst made a small, compact enlarger but I think it was limited to 35mm. We had one at our paper in a kit we affectionately referred to as "the Road Warrior." It was a darkroom in a trunk that we set-up typically in hotel bathrooms for processing and printing away from the office.
The small enlargers are inherently wobbly. If you plan to set the baseboard on the toilet seat and trays in the tub, consider a pair of eye screws in walls opposite each other and bungee cord the enlarger column into place. That is if your spouse will allow such a change in decor.
If your ceiling light fixture takes average screw-in bulbs consider replacing them with safe bulbs rather than adding an entire fixture.
When there's a will, there's a way. 😉
Both shared a problem, albeit small one at the time, the aluminum lock screw would quite easily snap, they were commonly available from the dealers.
I guess the new name reflected the SI system? 6x6 as opposed to 2 1/4 x 2 1/4 ;-)
All this talk of repairs? Other than the lock screw, a replacement for a too small base, and some bulbs, -- most enlargers just kept on going-- I even sold my first enlarger, a Federal, to trade for the Omega, and sold that to pay for the first 45m, so all my early investments were recouped 100%, hard enough to say in most cases. Over the years I stuck with the Beseler 45m because it worked, the color head fit, it did not break, and I accumulated plenty of lens boards and film holders, which can easily equal the cost of the enlarger. I had some custom cut as well, not too difficult a matter.
Loved the Minolta color head for the 45M, you want red, you add red, -- and before that the Fred Picker cold light head for B&W, these things are probably around, but the dealers at Camera shows just hardly can be bothered to bring them around-- last Minolta color head with a complete double set of bulbs went for $125 in the box years back, and several enlargers went in to my car's trunk for delivery to the local schools for free. May be time to send them some more, in case someone still uses them. Some of the local schools do a good job in traditional photography.
Freestyle used to sell the Meopta enlargers and parts in the US, they also built one that broke down to a suitcase size box.
I do hear that big enlargers are still bringing money.
Regards, John