Again, it come to participation. The more of us participate in IPMS event , the more it will be accepted. However, and her I go again, if we really are to be a truly integrated member of the IPMS, they will have to drop the P in IPMS or have the P stand for something else ( pragmatic, pretty good, part time, etc... - joking ).
As others noted. If you bring your paper models to your club meetings, shows, event, everyone loves it. I never had any issues. I would like to get that acceptance officially at the National IPMS conventions with categories that recognize other than plastic as a medium. It is not common to find an official category. At best, there is the "other" category.
Cheers
Isaac