Time to take a (short) break from talking about migrating Notes applications to SharePoint.  It looks like the Notes Migrator for Exchange team has been busy working on coexistence solutions.  To quote their literature:

"A Lotus Notes transition to Microsoft Exchange Server does not happen overnight—it usually takes weeks, months, or even as long as a year or two for large organizations. During this time, the two environments must coexist seamlessly to ensure smooth daily operations: for example, users must be able to use e-mail and schedule meetings, whether they are on Notes or Exchange.

Quest Coexistence Manager for Notes complements Notes Migrator for Exchange to ensure a seamless migration from IBM Lotus Notes to Microsoft Exchange through high-fidelity e-mail, calendaring and document hyperlink coexistence. It also delivers ongoing coexistence for organizations that must maintain the two environments for a prolonged period of time."

Here is the press release: http://www.quest.com/newsroom/news-releases-show.aspx?contentid=8806.

And here is the product page (with data sheets, etc.): http://www.quest.com/coexistence-manager-for-notes.