>I think my licensing is OK. The license is per server. The COM (a single instance) sits in the middle receiving update requests form users and then passing them along to SQL Server. No user connects to SQL Server directly.

If more than one user has a reference to a DCOM object simultaneously, it is NOT a single instance, and legally requires that you purchase a license for each simultaneous reference. There are no free lunches as far as licenses go, no matter how you creatively configure your server. I highly recommend that you call MS to ask about this, especially since your strategy is now posted on a board that MS employees frequent. You may find that I am wrong here, but better safe than sorry.