Surprisingly I've received some PM's seriously expressing interest in housing co-ops. The best resource for forming or sustaining a housing co-op has to be NASCO, the National Association of Student Co-operative Organizations headquarted in Ann Arbor, Michigan. Several ex-Rivendwellers spent years working for NASCO. They deal with both student and non-student co-ops, and everything from large apartment-like complexes to smaller co-ops like Rivendell.