Check this out:

http://cgi.ebay.com/Apple-Macintosh-Video-Adapter-SE-or-SE-30-Model-2703_W0QQitemZ200333659617QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item200333659617&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A1%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A5%7C294%3A50

It's a cable which plugs into the SE's logic board and internal display cable, but piggybacks what looks roughly like a VGA port for external use. Any ideas?