As far as i understood from the above discussion, i feel, if email == device which can be conveyed by above 65b statement. It can very well be accepted as evidence. Email can rarely be sent by other individuals, because its password protected.
Submitting a print out on a piece of paper, i guess that could be ruled out , since photoshopping can produce zillion copies of any kind of email or chat or anything.
But again, i have this doubt, if its a conversation, then probably just a single email do not make much sense, because one has to go through other previous emails to know what has exactly being conveyed in this email does make some sense. in this case, you might have to prove that the whole conversation is intact without a single message being deleted.
Having said all the above, law assumes that the email has been sent from your email address, thats it, the owner can very well claim that the email is not sent by him. But he has to prove his argument, in many cases its difficult to prove it because there would be so many mails sent along with aforementioned evidence.