Do you think there will be fuel-efficient vehicles that are up-armored in the near future for the US Army?

Tactical equipment are not road cruisers, they are heavy and designed for off road use. Efficiency will improve over time, but will never be effective with what a civilian, including those in government offices, consider efficient. Of course, if you really want to give them cardiac arrest, turn the conversation to how much JP helicopters pump out when the load is so heavy that lift doesn't equal load.

Eventually yeah. The technology is advancing quite rapidly and won't be as cost prohibitive as it is now. I don't see it happening in my lifetime, but it will happen.