I've spoken with two organisations who want to switch over to Foundations (one already has) and they both asked the same bleeding obvious question:
Can I get an upgrade from my existing Domino server and client licences?
The answer is no. Lotus Foundations provides a range of IT functions and providing email + calendaring + support for other Notes applications is only one part of the picture. The Linux-based O/S with web server plus integrated firewall and automated data backup plus a range of network domain features makes a very attractive alternative for small organisations who are dreading (or perhaps already regretting) an upgrade from NT to Microsoft's Active directory.
IMHO IBM is right in positioning LFS as a whole new ball game but I still think they should give a partial credit towards an upgrade from existing Notes/Domino licences. Perhaps allow any existing licences to be credited as a payment for the following years maintenance cost.