There is a 1600 Pan--something_or_other that Kodak
makes
that is also fine grain. I've used it to make C size blowups
of astro pictures. It is hard to find but it is available.
Most places I went would tell me that it was only use by
professionals and they didn't carry it. I wish I could
remember that name.
There are some specialty films Kodak sells that (I think) come from
their movie film stocks.