We're actually aiming at creating a scooter first, and other vehicles later.
The hydrogen tanks are much more sophisticated than we need. In particular they require a plastic liner (because hydrogen is so damned small). We just need carbon fiber wound tanks. These are manufactured to a higher precision but are not fundamentally different from 300 bar tanks which are fairly cheap (ie: you can buy single quantities of 9 L tanks for $500 - $600).
It's only a guess, but we think we can keep the tank price for a scooter below $1000, and for a car, below $3000. This is dependent on carbon fiber prices, and how efficient we can make the engine and drivetrain.
The important thing is that we can expect prices to improve handsomely while t goes to infinity, whereas batteries have had a lot of the manufacturing improvements that they're going to get.
and we have to aim at a substantially more efficient vehicle
Against which car models (once you are done marketing the scooter) are you intending for your car to compete? Camry/Accord?
But compared to batteries they're very, very cheap.
What tank-prices are you figuring? $4,000?
http://www.google.com/search?q=hydrogen+car+tank+costs