I’m using a completely different theme for each blog.
BUT, I’d like my readers to see exactly the same navigation bar across the top of each page across the entire website — with links to the homepage, forum, each of the multiple blogs, etc. Right now, each of my multiple blogs has its own navigation bars (which I will keep), but I’d like a separate “global navigation bar” across the top of the entire website.
You have two options that come to mind with only one cup of coffee in me. First which is probably the easiest is to create a separate php menu bar and store it in the root directory. Alternately you can code the menu bar into the header of each blog and rely on the blogs style sheet to do the formatting. Either way you go you will be hand coding the links.