If you're not averse to stripping old ones, some of the old mac Quadras can be picked up really cheap (at least they can here) and they carry 72 pin simm sockets. All of my LC475 and Quadra 605s have a socket with the metal clips on them, and they typically go for $5 to $15 Australian. Centris/Quadra 650 and 800s have more sockets, and often don't go for much more.
dana