This may have already been mentioned, but was there every any additional thought given to letting users accumulate support points for buying paid accounts? (This could also be expanded to buying LJ shirts and the ilk, once those are available). The support system is already pretty good (and a basic feature of LJ), but doing this might help convince users to close their requests when they're done and put more thought into their replies and not just sit and guess idly.
I dunno ... is this still something that people want to do?