A friend of mine is working on this project:

Terrestrial Return Vehicle for International
Space Station National Laboratory
http://intuitivemachines.com/aerospace/trv/

This looks to be interesting since it fulfills a need to return
experimental results to earth in a timely manner.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer