Ford sees the cost of hybrid vehicles dropping in the next 5-7 years, according to VP of product creation Phil Martens. He claims that the biggest challenge is getting the customer to accept rapid changes in the car market. I'd counter that decreasing the cost of hybrid drive components is going to be a far more difficult task, considering how much energy is consumed during the production of semiconductors, batteries, and so on. That's not to say it's an impossible job; just a damn tough one. Martens mentions that the ultimate in efficiency, short of fuel cells, would be a diesel hybrid. That likely brings the additional challenge of designing a CVT that can handle the increased torque of a diesel (that is, unless a series architecture is employed or if they just use a stepped-ratio trans).