Is this sentence correct:
1) At the library, for certain films there are two or even more copies, but for Antonioni's 'Blowup' there is only one copy.
2) The library has two or even more copies of certain films, but there is only one copy of Antonioni's 'Blowup'.
I think '2' is fine and that is the one I would use. I am not sure at all about '1'.
Use 2, and "two or more" rather than "two or even more".