View with data from many databases
It seems to me that your application has a pretty ugly architecture. Try to refactor it or you will have troubles.
Anyway, you can try to cache your suppliers' data to your own database (single) and save some resources.
I'm building site in django, which lists items of many suppliers. Each supplier has own big database and make changes quite often. I have to be aware of all changes in no more than 60 minutes. There are about 10m items to display. How to implement all that in a efficient way?