Yes, there are a few
Zero Motorcycles have quite a few models that are available for purchase right now. They are up to 67HP and a 197 mile range.
Harley Davidson has a model that should be released soon. They are touring the country with them and allowing people to test drive them at the moment while they further develop their technology.
I would imagine that the increased difficulty, if any, would revolve around smaller components packed into a tighter package. As well, I would imagine that cooling would be a simpler task. The Tesla batteries are buried in the undercarriage whereas motorcycles are more exposed thus allowing for a simpler cooling solutions with fins for cooling the batteries and electric motor more exposed to the environment.
Here is an image of the Harley Davidson electric motorcycle
Here is an image of the Zero Model S electric motorcycle
Both are viable vehicles. I have ridden the Zero S at Laguna Seca when they attended an event to promote their vehicle. It was very quick and handled quite well. It even emulated engine braking with electromagnetic resistance used for regenerative braking.