According to this story from the AF Times, not only are all the services expanding their JROTC programs (from 3,400 to 3,700), which we've known about for a while, but it looks like the Army is starting up a middle-school version of JROTC as well. http://www.airforcetimes.com/news/2009/12/gns_jrotc_123109/ (http://www.airforcetimes.com/news/2009/12/gns_jrotc_123109/)
Up till now, CAP's main advantages over JROTC has been the opportunity to get involved much earlier as well as the possibility of ES involvement. If we have to start competing for the younger demographic I think this will hurt us in the larger towns where JROTC programs are usually found, and presumably where they would open middle school programs.
By the way, no mention of CAP as an alternative to JROTC.
Well Chicago public schools already has a middle school program http://chicagojrotc.com/cadet_corps/?rn=9391461