The number of pages is saved as two bytes in the DVI file header. This means that there is this limit of 65536 pages that cannot be changed without breaking of backwards compatibility, so it is unlikely to happen.Could not the default remain 65536 pages, but have some user configuration parameter they can change? This way there is no backwards compatibility issues. right?
This is not something Michal can do, write to the texlive mailing list. -- Ulrike Fischer
