yeah, they have them available for the rental market. Pittsburgh Full throttle has them. They are pretty heavy due to battery. They have awesome take off speed but don’t handle through the turns very well. You’re talking 500 lbs compared to my gas racing kart at 375. Hard to get the inside rear to lift in corners when the kart is so heavy.
Going to be a similar issue with electric dirt bike. Back in the day my KDX200 weighed 225 lbs which allowed me to throw it anywhere I wanted on the trails. The extra weight of a battery is going to make the dirt bike more like an Enduro bike KLR600. Also hills are a killer for electric bikes and I’m sure would also be an issue on electric dirt bikes. Good luck though.