Internal combustion with hydrogen is NOT necessecarily cleaner than burning gasoline. You bring up a good point about production. The current best source of hydrogen is hydro-carbons (crude oil). So we will substitute a product that requires more refining and is more expensive to make but still continue to use the same raw ingredient? Throws the argument for reducing dependance on foreign oil out the window. But back to pollution. If you burn hydrogen you get water right? Yes, in a PURE OXYGEN environment that's true. But we are going to burn hydrogen in an environment that is not pure oxygen. A large component of air is Nitrogen. When you burn nitrogen you get oxides of nitrogen (NOx) ie a major component of smog. There goes the pollution argument.

There is another way to use hydrogen for power and that is in a fuel cell. There are many designs but the technological hurdles are pretty high.

So no, I don't see it happening in the near future.