A friction drive design of a few years ago, a few have initiated the same principle in their design over the last few years and mostly failed I think. The add is 3 years old, simple but not cheap if you don't back it on a kick starter. Cost is circa 750 euros.
The latest one to start marketing the Friction drive is Revolution Works aka Revos in Bristol, first production units should be released soon to backers of the kickstarter.