If a sub-$10k car could be sold today in the U.S. profitably, a car company would've done it already. Look at the Versa, old Neon, base-model KIA's and Hyundais...nothing starts at $9995 anymore...
Love the idea, but unless regulations change there is no way a Tata Nano is coming to the States for less than $10k. Mahindra trucks failed, and I'm afraid this will never work either.
I've toyed with the idea of starting a company that makes true kit cars - buy a body, engine/transmission combo, wheels, etc, and build it yourself for cheap - but you can only sell a thousand or so before the gubmint starts making you play by the EPA/CAFE/NHTSA rules....then the cost goes up dramatically. Tough to recoup millions in design/tooling/manufacturing costs when you're trying to make a few bucks off of 1- to 2 thousand cars a year.
U.S.A. = TPMS, 15 airbags, 3 catalytic converters, crumple zones, automatic transmissions but still need to get 40mpg, etc etc etc:thumbdown