If more clients supported it, then you would not need a separate IP for every SSL enabled virtual host. That would be cool.
Here is an example config:
Quote from TLS Upgrade Example:
<VirtualHost *:80> ServerName svn.foo.com CustomLog logs/access_log common ErrorLog logs/error_log <b>SSLEngine Optional</b> SSLCertificateFile conf/svn.foo.com.cert SSLCertificateKeyFile conf/svn.foo.com.key <b>SSLRequireSSL</b> </VirtualHost>
There are two key parts, first, setting SSLEngine to 'optional', this allows normal unencrypted HTTP requests initially. Second, the SSLRequireSSL bit tells the client that it must ugprade to SSL to continue with any requests. Its pretty sweet to see it in action. Sort of like START_TLS for other protocols, but designed to work within HTTP's paradign.
I have submitted a bug to Mozilla, asking for support. It doesn't look like any Mozilla developers are interested yet. darn.
I guess I will keep making wishes for support of cool protocols features. I am not motivated enough to attempt to write a patch for mozilla yet.