They exist, but you are probably the only one willing to buy one at ridiculous price, or the military.There is a new battery technology coming out every month. I am still waiting for smart phones that fully charge in 5 minutes and last all week. Surely these things exist in the lab but by the time the general public gets one its 5 - 10 years down the line.
Seriously, people love to buy toys that last half a day worth of charge if they look sexy.