An interesting idea but noone really wants it
Although it's an interesting idea, the feedback we've seen on the community IdeaJam has been pretty overwhelmingly against open sourcing Domino. The way that Domino is going at the moment seems pretty good without a massive change in the way it is managed and developed:
http://ideajam.net/IdeaJam/P/ij.nsf/0/834A4BA0093A41F48625752600585353?OpenDocument