There might be a market for an e-paper based version of this that shows an entire day or week of schedule.
I've been in a few buildings where each door had a fat 15" LCD screen mounted beside it, displaying current and upcoming reservations. Even at my university they were beginning to implement them. You probably need good connections with commercial builders to compete in that space, though.
[1] http://www.crestron.com/resources/product_and_programming_re...