BuddyPress.org

I actually think that a (child-) theme should just be generic and not network specific. That should be the job of one or maybe even more plugins. If those plugins all use the normal BP default theme markup, you can use any kind of plugin to create exactly the kind of community you want with exactly the kind of look you want. A theme should stay away from adding functionality as far as possible. The only exception I can think of is a mobile theme.