I think Sheehan could be a really good guest on the paracast. I really enjoyed his talk at the X Conference a couple years ago.
He is a guy with high credentials (former General Council of the Jesuits) a 'super liberal' one time DC insider who has first hand experience with the government cover-up and tried to get info from the Vatican personally. I believe he was also involved in the Iran Contra affair.
I didn't know he was still working with Greer, but I wouldn't let that effect whether he is worth booking since a lot of his knowledge and experience I think, is mostly independant/outside of Greer's world.
Sheehan is the type of guy that may actually be in touch with people like Jon Podesta etc... At the same time, Sheehan might be out to lunch with Alfred Webre and the exopolitics peeps, I don't know, but it is definitley worth Gene and David looking into because of his professional background and his personal UFO cover-up experience with the government.
Here is his bio that I found online, which is easy to find, just google him -
http://www.ufoevidence.org/researchers/detail47.htm:
Daniel Sheehan, JD, is a graduate of Harvard Law School, a former Director of the Christic Institute, and is a Professor of World Politics at the University of California. Mr. Sheehan has a long and distinguished history as public interest counsel, and was legal counsel in the Pentagon Papers case, the Iran-Contra, Three Mile Island, and Karen Silkwood cases, as well as many other high profile cases. "During my thirty years in the field of public interest law and public policy, I have supervised professional investigations into the illegal smuggling of weapons-grade plutonium, the illegal supply of arms to terrorist organizations by covert operations and government agents, and into ultra-"black" weapons programs unknown even to the most trusted congressional officials. I have come to believe that keeping weapons out of interplanetary space is the most important contribution we can make to the future of this planet. The time to begin this task is now.