OP didn't specify what kind of fermenter so hard to recommend specific models. Assuming 50L you're referring to being able to fit a 50L kegmenter? Also no mention of double batches in OP.
@reddog As for what I've used in the past, I had a kelvinator 140L impression series (M140D-R) and could fit a standard 30L plastic fermenter (without any mods). Shelves removed from the door and weren't moulded, freezer was in the corner and fermenter was short enough to fit.
Other bar fridge was a westinghouse 140L (RA141S-R) which I bent the cooling plate down 90 degrees. I wanted to ferment under pressure and also ended up hacking the insulation off the door and could squeeze two 19L cornies and a 2x 5L demijon (or half kegs e.g. 9.5L) on the hump, so I could do two batches (split between four vessels - not ideal but it suited as a proof of concept).
I also saw recently someone converted a small bar fridge to a 2x kegerator without removing anything (no freezer section - model WRM1400WD) -
PXL-20210623-055454627
There are also commercial versions that go through catering auctions at times, such as frigidaire, anvil, FED and other brands which often don't have the freezer compartment, and a smaller hump recessed further back (
Fed Bar Fridge Auction (0080-7028808) | Grays Australia). The FED fridge in the link is almost identical to the kegerators you can buy.
Alternatively if you can find a taller bar fridge it could work, something like this (990mm tall).
View attachment 120824
So it comes back to how long you want to wait, how much space you have, how much you have to spend and what you want to ferment in. You can find plenty of options that work, but how well they work or how flexible they are will vary, so it's really down to your own needs and preference. If you have the $ for 2x kegerators and that's an easy option and solves the problem, perfect. Also depends when you say conditioning, if you're talking about moving it to a keg first - so your size requirements may be less.
I went for a taller upright fridge to fit an all rounder or a conical or similar to have the extra headspace in the fridge.