The POINT here is that it's FREE advertising. I think I agree with bwcoyote's post to let the hobbyists pick the theme days (like choosing the theme days the week before, so everyone gets a chance to get in on it!).
This board was built for providers to show themselves off to the hobbyists, therefore it should be the hobbyists choice for what they want to see. We have enough hobbyists on here to get make this happen.
I agree: the hobbyist who gets up on Friday and posts first chooses the themes for the following week. That would be SO simple (not quite as simple as Daego's try at it - which worked better IMHO - but still simple).
The final result will be the providers/agencies who supply what the hobbyists "demand" will reap the benefit. Simple supply and demand theory in effect.