Hot of the presses, some good news for those looking to use Domino 8.5.1 and Sametime 8.5 community server or 'classic' meetings server. IBM will now provide technical support to customers using this configuration. Here is the official technote with the official support statement.
We plan to continue testing Domino 8.5.1 configuration for inclusion in a maintenance release of Sametime 8.5, currently targeted for release in 1H 2010.
Sametime 8.5 and Domino 8.5.1 updated support statement