Only in the r/c stuff. LiPo.
I recently checked out a Lithium for the Harley. It came uncharged so I was told I needed a special charger for it. Also, that if completely disconnected it will never lose a charge. However in cold weather applications like snowmobiles, they barely function.
My DR is going to need a battery soon so I'll be tuning into this thread as well to see what comes up.