Fuel cells are definately in the early stages. However, I don't think the forklift industry need wait on the automobile industry to pioneer this. Cost is definitly an issue but from an infrastructure standpoint forklifts lead the way.

With a large user you have quite a captive audience. Assume 50-100 units all in 1 facility. Logistically it would be easier to access 50-100 forklifts than 50-100 automobiles. An on-site fueling station would be simple compared to fitting multiple gas stations with equipment to meet a limited demand.

Companies like Cellex and General Hydrogen have tested products in warehousing applications.