Actually, it was said in anime by reanimated Tobirama Senju that the Uchiha's brains released a special type of chakra upon experiencing a sad moment. So I feel that the eyes don't really matter here.
I think that if a skilled medical nin is able to transplant an Uchiha brain into a rabbit, have it reproduce and then kill the baby rabbit a few days later, the rabbit should awaken the Sharingan and then further a Mangekyou Sharingan. This could be a way to cultivate multiple Sharingan (Sharingan farm).
Then the rabbit's eye should be taken out and replaced with a normal eye (probably from the person who wants the Sharingan). Finally, transplant the eye into the normal person and he gets a free Eternal Mangekyou Sharingan.