Tom Persinger’s f295, home of the excellent International Pinhole Photography Discussion Forum, have added the DIY (Do It Yourself) Photography Discussion Forum, "dedicated to the exploration and discussion of self-made photographic equipment and materials".
The quality of conversation, experimentation, knowledge, and helpfulness on the pinhole forum is exceptionally high, and I expect this to be no different. Camera builders, lens hackers, homemade kit traders, come check it out!
(Note that this about a day old, so it may take some time to get up to speed.)