Multigroup (CCK3) / FlexiField-like solution for compound fields?
For the moment, I'm implementing this via Field collection. Granted, that is still very early development. 

If somebody could provide a list of solutions in the "group content fields together and allow an infinite number of these groups via the 'add another' button", I'll accept that as my answer. I may have to upgrade my FlexiField project to D7 at some point and there's currently no clear upgrade path with that module.