I just read this press release about having relay satellites in "stable" lunar orbits for continuous Earth - Shackleton Station communication.
http://science.nasa.gov/headlines/y2006/30nov_highorbit.htm
It says "High-inclination, highly elliptical orbits being cheapest and most stable for communications satellites around the Moon? To Earth-centered satellite engineers used to thinking in terms of circular equatorial orbits, "it's a new paradigm," Ely declares."
Now, I'm no engineer or designer or anything, but wouldn't several line of sight relay stations, or probably a really really long fiber optic to a transmitter placed somewhere on the moon that faces the earth be much cheaper than the launch and operations of three relay satellites?
Or am I reading too much into this article?