Yes, Cruise control WAS available as an option.
I, like puggy went the manual route. I actually made my own throttle lock which worked really well. Of course the manual ones wont hold speed, only throttle position. So, any inclines or declines will result in change of speed. Not a big deal for the most part.
However, to the OP's post, I personally don't think it will be a quick plug and play solution.