Just upgraded to CrossOver 5, and I can confirm that Endnote 6 still functions as reported before. Not perfectly but definately usable.
I run Slackware-current (10.2) with Fluxbox-cvs (0.9.14) as desktop and 2.6.13.4 kernel on IBM T41 laptop.
After upgrading to v5.0, Endnote started with the known bug, with the window where one is supposed to choose the database to open hanging. This can easily be circumvented with the following (this has been reported before, but just in case anyone missed it).
Open Endnote from command line with the default database.
~/cxoffice/bin/wine ~/.cxoffice/dotwine/fake_windows/Program\\ Files/EndNote//EndNote6.EXE <your-favourite-database-here>
Cheers, Leon.