RFC 2109 recommends that the minimal cookie size supported by the client is
4096 bytes. This has become a pretty standard value, and if your server sends
larger cookies than that it's considered a no-no.

This module provides a pretty simple interface to generate small cookies that
are under a certain limit, without wasting too much effort.

WWW: http://search.cpan.org/dist/CGI-Cookie-Splitter/