I was driving on I89 to Vermont a couple of weeks ago and a semi blew by me with an aero mod on the back. I had never seen this one before, so I caught up to him and snapped a few photos. There was no turbulence when I was tucked in behind him; or at least not nearly as much as trucks without this mod.
Side skirts are popular here in Maine too. Seems CA says all trucks coming into their state will have to have them by 2013 (or thereabouts with the "phase in" period) which means all long haul trucks will have them by then. I would assume even short haulers will have pretty much adopted them by that time too.
As for the rear section, I could see that being a reality soon too. Sure there's some lighting issues that would need to be addressed, as well as convenience (how easy is it to fold up/away at a loading dock), and overall increase in length issues, but I think it's only a matter of "proving" their huge increases in FE and they'll be in widespread use pronto. The website Vetteowner gave says the organization wants a total of 15% increase in FE with those two mods and a bridge between the cab and trailer. How might that work? Flexible rubber sides? Hmm....