We already know that a 4 dton brig can hold up to 6 prisoners and can "uncomfortably" hold up to 12 (and I'm pretty sure 6/brig is still far from comfy), I'd give these sorts of accommodations a total size of 1dton/person (which includes access space, corridors, as well as a fresher, and a minigalley for every few units (maybe it's more like 4 dtons for 4 units). Naturally, anyone except colonists, refugees, and people who *really* need to get off-planet asap won't take these sorts of accommodations, so it will be pretty specialized. Heck, given that military barracks take up 2 dtons/person, I'm assuming that even most soldiers would balk at a week or more in these sorts of quarters.