TITLE: Proper scheme such that every vector bundle is trivial
QUESTION [6 upvotes]: It is claimed here that there exist proper schemes (probably over a field but not explicitly stated) with trivial Picard group. This means that every locally free $O_X$-module of rank 1 is trivial. 
Do there exist proper schemes over a field such that every locally free $O_X$-module of finite rank is trivial?
Maybe it is easier to give some examples with algebraic spaces, but the accepted answer should give a scheme. 
EDIT: examples should be positive-dimensional.

REPLY [5 votes]: According to this paper it is not known if every proper algebraic scheme admits nontrivial vector bundles. Partial results can be found here.