This is the fight i want to see. If Lesnar would keep him up on his feet, Lesnar would beat the shit out of Kimbo. I know Kimbo has gone through training with grappling, but he is still most comfortable with stand up fighting, so I don't see Kimbo trying to take Lesnar down. Lesnar would take this fight if it were to happen.
IMO, if you give Lesnar another 6 months of training, he'll be unstoppable.