As I said on another thread recently, birdie, how do these people who see Jesus in drying plaster and so on know what they are looking for? Where are the photographs for reference?
And I always laugh out loud when a hysterical teenager or two see a Virgin Mary who is tall and slim with a peaches-and-cream complexion, often with blonde hair and maybe even wearing a crucifix! She would, as you say, be swarthy, to which I would add a Jewish nose, dark to black hair, a shortish build and possibly slightly plump due to a diet laced with olives and fatty lamb. Just a guess, but an educated one.
The original question is a daft one until you have established (a) that Jesus existed, and (b) that he had the magical powers to 'come back' (from where?). Both thngs are imposible to prove or even offer good evidence for. Still, this is the R&S site.