Actually, no. When you make the connection to the server, it
automatically spits it out as a 'hello' message. Just have the
browsers wait for one line of output, then parse it to see if it
accepts http/1.0 requests, then send the appropriate request. It
might mean a slight slowdown for sites halfway around the globe, but
then the connection won't be blazingly fast anyway. :)
I had always wondered why this wasn't in the HTTP spec, since most
of the other protocols seem to use it (SMTP, NNTP, POP, etc).
The only problem would be re-releasing new versions of the clients,
but thats no big deal. It would be critical to time the release of
new clients with the installation of the new servers, or else things
like GIFS and compressed images would be totally screwed.