Today we've added SSL support to our Selenium grid, you can now test HTTPs pages without problems. Self-signed and regular SSL certificates should be automatically accepted on our browsers.
We are using the CyberVillians certificate on Windows, which is bundled in Selenium RC, and is documented on http://blog.mogotest.com/2010/04/13/how-to-accept-self-signed-ssl-certificates-in-selenium/
There may still be some issues with Safari and self-signed certificates, if you do encounter a problem on Safari, please let us know. Also, right now we're redirecting all safari requests to safariproxy since it seems more stable. This should not have any effect on speed or tests.
On another note, we've been preparing our grid for unicode support. We've installed the necessary packages to support any language: from Cyrillic characters to Japanese Kanji.