I too spend sometime in auto and support, for a bit. I was told in the late 70's and the Diesel Rabbit showing up in the Michigan Marketplace, Diesel prices missttterriousllly went up quite a bit... Hmmm what a cowinkadink...
BTW IMHO Smart money is on CNG.
Do some research on the recent DOE type project, of going the next step with our current CNG infrastructure, i.e. natural gas to our homes. A low-cost low pressure pump and a normally shaped tank that holds 30% more than it is supposed too via nano-tech and other lung type internal absorbent materials @ a lower pressure is the goal. If they do it IMHO it is a game changer...
go here: http://www.greencarcongress.com/2012/07/move-20120712.html
The home fueling deal is currently the major issue I see.
I’d buy a nat gas Honda (made here in Indiana) but the compressors are currently expensive and unreliable.
But that has to be a solvable engineering problem.