A last comment, a LEO would be virtually worthless for Emergency NET communications and HF is still a viable and reliable means of communications...
Well, I still think a bunch of 145.825 APRS digipeating satellites in LEO that would allow text-messaging from anywhere in the world at any time, downlinked into the APRS-Internet system and hence global internet connectivity is still a great way to go for basic messaging for emergency response. With just 6 such tiny 4" cubesats, you could get a message in-or-out with no more than a half hour wait from the front panel of your APRS mobile radio. With a dozen of these, you could have global communications anywhere instantly or with no more than a 5 minute wait.
Our goal is to get more of these up there to join the ISS digipeater, but of the 4 we have lanuched so far, all were short-term orbits and so the most we have ever had operational at one time was 3 (PCSAT-1, ANDE and RAFT). That is one of the main reasons we wanted to see ISS on 145.825 to join the constellation. ISS was still on 145.800 during most of the life of those three birds (which were all on 145.825)
Today, with 6 AA NiCd's, a 19" whip antennna, and a 3.4" square APRS Microtacker TNC/Radio you can throw together an APRS satellite for under $400. Add cheap solar panels, a lot of sweat equity and then find a school to provide the $50,000 launch, and bingo, A LEO satellite with great utility that anyone can use while mobile for text messsaging and email from the front panel of their APRS radio.
Please see the Microtrack TNC/Radio which can serve as the entire Comms, Command, Control and Telemetry module:
http://www.byonics.com/microtrak/mt-tt4.php
And see our cubesat project: http://www.aprs.org/psat.html though this web page needs to be significanly updated..
Bob, WB4APR