4
I run (amongst other things) a member site for a 17thC re-enactment society. It uses nothing other than available modules:
See
the site credits for a list of user side modules that it uses.
Most modules have limited access to members only (at least for adding content.) The myAlbum module is cloned to create a totally private photo gallery to supplement the publicly available pics.
Member administration is currently done off-line but enquiry forms and the like are handled by Liaise and teh submitted details sent direct to the appropriate person to deal with. I do have plans to write a module that will handle member details and accounting but I'm waiting for core XOOPS team to incorporate the XOOPS 2.2 extended profiles into the 2.3 build (and of course release 2.3!).