This one here
is a portable wet plate darkroom. Not exactly what you're looking for, but it might give you some ideas.
Before I built my darkroom, I used to keep all my darkroom equipment and supplies in medium-sized cardboard box. I set up and processed in the bathroom. It wasn't a bad setup because I had an exhaust fan, a sink with running water, a shower rod that I repositioned over the bathtub to hang film, no windows, and I could easily block the minimal amount of light coming around the doorframe, especially if I kept the hall light turned off.
Of course, you don't really need a darkroom to develop roll film. You can do it in your kitchen. But the bathroom setup came in handy anyway, since it was a little used guest bathroom. Especially handy for enlarging and printing. I set up the enlarger on the vanity, and my processing trays on a board that spanned the bathtub.