I didn't know where to post this, so I'll post it here for now.
For the fun of it, I've been testing this morning using the forums with its HTTPS address. For the most part, it's actually working pretty good, but I do notice a couple issues...
1. I can't set a HTTPS link for my avatar. I try to change my avatar's URL address from
http://i.imgur.com/7u4jHqt.png to
https://i.imgur.com/7u4jHqt.png (which is a valid link) causes the forum to reset to using no avatar at all. Reverting back to the HTTP link works. This is a known issue with SMF, which can be worked around:
https://www.simplemachines.org/community/index.php?topic=551556.0 and
http://www.simplemachines.org/community/index.php?topic=541642.02. The mixed content warnings. This is the big one, but it can be worked around as well. For SMF 2.0 an
image proxy can be used. Or you guys can wait for SMF 2.1, which will support this built-in (when this is released as stable, is anyone's guess).
If those two issues are worked around, you can actually force enable HTTPS as the default for the forums.
The main site? IMO, I've done some testing there and everything looks good. You guys *could* force enable HTTPS on the main site already!