Howdy MissB, welcome. I was going to suggest the Titan as well. Great folks and the kit gets awesome reviews. The Titan is the blue bike
with the engine over the rear wheel. Dax also has an advertisment on upper left of this page. Using a used bike, you want to make sure it is in good repair and tuned up.
Folks have put China Girls (HT) kits on step threw frames as well. But a bit of a pain.