sunblock_boy and a few other coworkers told me about this crazy idea yesterday and I've spent some of today researching it. The car's lighter than normal, light enough that the pneumatic engine with electric assist can get it up to 100Km/H for sustained periods.
This seems like an excellent idea. I don't know where we'll get the 4500psi that's required, but the reduction in emissions and small electric cost seems to make it worth pursuing. I've even put my name on their list of people to be contacted when they get into production. Of course, at the point I'd owe sunblock_boy $1 because I bet him that they'd never be available. Big oil and car companies just have too much leverage to let such a competitor into the market.