A question about your first idea...Have you spoken to any of the wireless carriers about massive amounts of text messaging? I know from personal experience there was a physical limit of 10K messages per hour on the Nextel network. This may have increase and it may be way more than you are planning, but you should contact a carrier to see if there are any lower limits to prevent spam. Even 100 texts going out simultaneously may be suspicious to a carrier.

Otherwise, I think it's a great idea on a local level.