Yes, at the very least, that would help immensely. There should be a common header that can be used on all (sub)sites. I've been doing some research on PHPBB, and it seems that should be possible. I don't know about the wiki, I didn't look into that.
I'd love to help out with some of this, let me know what I can do.
I'm not so sure about the Wiki either, I might be able to hack it in through CSS (no promises) otherwise I can just ask Wikidot if they can do some magic for us.
I can easily implement it on the two other sites if someone designs a top-bar that looks good in all the three sites:
Maybe, if anyone feels like it, someone who can design it can PR it to torque3d.org
, then I will attempt to get it in on the other two pages.