There was one Korean company that is coming out with a very nice e-bike mid-drive conversion kit in 2018. You don't lose the front derailleur. A cylindrical battery pack attaches to the motor and mounts under the downtube--no wires to a remote battery. Only the left crank arm is removed for installation. It's not on their web site yet. With other mid-drive conversions you only have a single chain wheel.

This company also had some very high quality bicycle lights, including a new 5000 lumen model. 500 lumen appears to be the low end now for lighting companies, 1500-2000 is mid-range, 2500-5000 is high-end. But like many companies, they won't sell through QBP and few shops will meet their MOQ. Very good marketing person, who spoke perfect English in the booth. The Korean companies tend to have their act together at trade shows.

http://www.luutech.com