I'm sure this is way out of your scope but we'd possibly be interested in paying for the development. Essentially, we run a network of forums in a particular niche and we'd like users to upgrade to a premium on any one site and have it be reflected on all sites. I assume users would be identified by email since account IDs are all different across the sites. Also, the database might be on a separate machine as the forums but my SA can handle all that. If you aren't interested then I have a developer who could probably implement this, assuming we have all the information necessary to pull it off. We'd pay for the lifetime licenses on 4 sites initially but eventually up to 12 if it all goes well.