How about several large 2'x3' LED panel connected to an keyboard mounted on a wooden (for burning) or metal frame.
Located off Esplanade at some of the O'clocks (3,4,6,8,9, center camp).
You can type messages on them, and the messages scroll through. Like at the airport, waiting for the departures!
At certain times in the night, a message like "Hug the person standing next to you" comes up and stays there for awhile.
Another step would be to have them be capable of sending messages from one to the other.
For example type, "Oliver I love you" and press the 6 button and the message goes to 6'oclock.
I may be able to obtain some cheap ($200) LED panels ~2'x3'. These are similar to the kind you see on the highway.
I'd (we'd) need to design a controller for them and figure out how to deal with the power issue.
Fun?
Sophi
mix-engineering.com