I just created this page, I don't mind if someone wants to help host with weekly themes. I had plans to even add this as a feature of streak club, where each week the theme is revealed. If people are interested in arranging that I'd be glad to set something up.
re: weekly beats themes, I think they were adhoc done on the forums. I know I never followed a theme for any of mine. I think that's cool too, if someone wants to make a theme thread here.