That's an awesome idea.
I like Blondieboo13's idea of having the one sign. You could also maybe make a standee that features as many villager faces as you can squeeze into the design. I've seen one like that before, with all the hamsters on it! It was really fun.
(Just a note about the sign limit, since I know you're well aware of it--it seems to be eight, unfortunately, and that's only if you don't have standees as well, so it's worse than we thought. At least, that's what happened to me--when I was building my Goblin town, I was going to have signs throughout the labyrinth, plus multiple standees. After all, all the ACNL guides I'd Googled said the sign limit was 10, and the standee limit was 8. But once I started building my standees and signs, Isabelle wouldn't let me build more than 8 combined total of the two. I wasn't near my PWP limit; she just would not allow more than 8 custom PWPs of any kind. I wound up having to just use patterns on the ground, which I know you said you'd rather not resort to.)