Have you seen Notes 6.5? They don't do what you've requested, but they have done a better job of integrating Sametime into Notes.
Which is great for my company, as it brings validation to something we first did almost a year ago ;-) We have started extending calendar events into sametime, for example we have an option that allows your Outlook calendar to manage your Sametime status description.
Carl
http://www.instant-tech.com