I've been seeing a lot of 3-D printed FDM parts showing up in labs in recent years. Of course you can't 3-D print an MBE or FIB, but maybe you could automate the manufacturing of some significant apparatus to the point where you really could download a cutfile from Thingiverse, cut it out on a CNC plasma table, and have it MIG-welded together by robots, so that, like custom T-shirts or FDM-printable parts, it can be cheap even without being high-volume. Even some high-vacuum apparatus might be accessible by that kind of route. A friend of mine has been doing a lot of optics fabrication via UV stereolithography.