I think you're mistaken. It appears the choice is moving from a RaQ with their assistance to a different server, or putting Plesk on a RaQ w/o a change to the OS. I don't see anything on their site about what you describe.
Dan,The e-mail came to me from plesk and forwarded it to the list. I don't describe neither vouch for anything :-)
I think more information can be obtained from sales@xxxxxxxxx -- Regards, Gaurav Sabharwal http://www.inwire.net