It seems that a few other bloggers have started providing some commentary on the Theatrum Machinaru... although we're still a long way from a micro-community.
Of particular interest is BibliOdyssey. Although young, it features sample plates from Bockler and Besson. Since Hooke owned a copy of Bockler's work I may want to revisit it. There are even some other Besson scans out there.