I couldn't care less what it's called (opt, programs, bullshit, whatever); I just think that keeping separate apps separate might make sense. Of course, then you get into the problem of having startup scripts for each of those apps, and they must currently be outside that structure, assuming you're using preinit. So maybe a really simple package database would be a good idea. If not, maybe a standard place for shared files within opt/whatever would work, like /opt/shared.