I'm kind of in the same boat here. I don't have as many as you do but I live in a single wide trailer. Usually when I sell/give away a machine I offer them a cabinet too if I have one that fits the machine. I try to talk it up by saying the cabinet can be used as a table or a desk, saves having to tote the machine from closet to table, etc..sometimes it works and they take one.
I've also gone after free cabinets if they have something I want like a knee control still in it or those front clips for a 301 cradle.
Cari