Question

Theoretically, what would constitute an ideal transplant?

Answer 1

Theoretically, organ transportation would constitute an ideal transplant.

Answer 2

I think you mean here organ transportation. 

An ideal organ transportation is within the same person - that way, that person's immunological system won't attack that person's new organ. 

Such transplantations are actually happening at times, in the case of skin drafts - a person's skin can be transplanted into another part of their body.