BPL won't happen any time soon - trials underway sure but no widespread adoption is scheduled anywhere to my knowledge (btw BPL seems to piss the Ham guys off like nothing else) - never mind the fact that no power companies are set up to provide the bandwidth it would take to support a community , plus the small coops that provide elec service in rural america arn't the type of folks you want running your broadband
Wireless - nothing on the horizion that will provide rural service - (southish states - pine trees - see Websters on "How to Stop Wireless Signals") also keep in mind the fact that you need bandwidth to support broadband and well not many companines are set up or can be set up for that in rural america
until Fiber to the house is a universal service type arrangment rural america for the most part is going to be broadband free
I'd love to be proven wrong though