Scott you are correct. One point though there will be no clustered index at all. They will all be non-clustered.
From http://msdn.microsoft.com/en-us/library/ms189049.aspx we find this:
A foreign key constraint does not have to be linked only to a primary key constraint in another table; it can also be defined to reference the columns of a UNIQUE constraint in another table.
(Emphasis mine.)
I have been through this exercise during the database design for Scout. We needed a design that would support inserts from synchronization of mobile device data. UNIQUEIDENTIFIER initially looked like the simplest solution to collision avoidance. I had to do all the research into the indexing of UNIQUEIDENTIFIER primary keys. We ran into the issues raised by the OP here. We scrapped UI altogether and wrote our own key authority.
ATBCharles Kincaid