Chris,
ok we have
Power Feed 2-wire > S3 switch > 3 wire to cieling > 3 wire from cieling to last S3

right?

If this is so, then there is only so much you can do by conventional means, being that you would like to retain the two switches AND have a constant hot available for the fan's pullcahin switch.

One unconventional scenario could be to install Lightolier Digital Dimmers www.lightolier.com 1-800-526-2731
p/n 85-0969B

These operate by sending a 'signal' as oposed to switching from traveler to traveler, the configuration you have can feed both locations ( thereby gaining a constant hot & nuetral @ the cieling location for the fan) and utilize the red as said signaler bettween the two switches.

The only other option are the remote controlled fan/lights, which would basically need the availability of the 'controller'
( looks like the TV channel remote) to be readily avaliable at both S3 locations
( dip switches would need to match up)

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