Adam, just one slick homepage. My congratulations!
Being a perfectionist, I feel with you. You are in a dilemma now.
The majority of forum users (which probably jump right into the forum w/o even visiting the home page) will not accept a change of forum standards from green to red.
On the other hand, clicking on a navigation item on the homepage leaves an odd feeling -- because red all of a sudden changes to green. And of course, Making a PentaxForums homepage red is a natural choice
What can you do?
Well, you could change all forum members settings from 'default skin' to 'green skin' -- and THEN change the 'default skin' to red. So, existing members will not be affected while new trespassers get a consistent experience.
Of course, this assumes that the auto-login feature works. It works for me (I always get the same skin back). But it doesn't seem to work for stewart_photo. So maybe, you first would have to investigate why skin selection didn't work for stewart_photo. And fix it. And then proceed as outlined above.
Of course, just an idea of what you could do about. I am fine with whatever you do.