Have you considered using slide-panel controls?
No question that "Hide object when" is fantastic (and looong-awaited)! But I agree with you that when a number of different conditionally visible objects are competing for the same patch of layout real estate in Layout mode, it could get cumbersome. I also wonder about the performance impact of having many objects on a layout with various conditional visibility rules individually applied.
If the objects and their conditions can be logically grouped, as in your case where each school has different layout needs, you could instead place a slide-panel control, disable the navigation dots and swipe gestures (most likely), and use script triggers to navigate (Go To Object) to the respective panel based on the value in the school field. That should be a lot easier to maintain and possibly a lesser impact of performance, as well.
I'm definitely going to be using slide panels a lot.
There's a great blog on this topic over at SeedCode, btw. Check it out.