it's -really- hard to allow unaffiliated groups into one's shop for liability reasons if you run a theatre shop, especially since you're dealing with significant and complicated life safety issues. it's one thing if your employee/member damages equipment and it breaks something in it's failure, it's another where someone else does, and it results in a life safety issue for an actor. i was always ok with loaning out tools that weren't in use for personal use of co-workers, but we never allowed any personal use of shop gear in the shop. (with the exception of say repairing one's own tool for use in the theatre)
there are however, a LOT of small theater companies who don't have a shop, and that may be something we could look at in terms of advertising/income/partnership.
i.e. a nfp theater co can use the shop for free in exchange for their left over materials being donated, and advertising space in their programs as a sponsor(maybe we "co-sponsor" each other), or we offer a "group" membership at discount, so that an organization can say pay the montly fee for 5 members, and have up to 10 use the space only for the specific group project. that may also work for say scouts who want to build a big project, they buy a group membership that allows them to -only- work on their project, but at a discount vs buying full memberships for everyone who would be in to work on it. (with the idea that a few folks will actually join)
side note, theeater shops generally don't have the electronics or CNC needs that we have interest in. very little in theatre is that fine tuned, but the basic wood, metal and sewing are all well within their pervue, although we probably don't need a wig shop, a dying facility might be interesting if we were going to include some of the craft mag sorts of projects.