I'm not certain, but before the 12th Amendment, every Elector had two votes. The could cast both for one candidate.
In the Constitution it says in Article II, Section 1, Clause 3 (since superceded):
The Electors shall meet in their respective States, and vote by Ballot for two Persons, of whom one at least shall not be an Inhabitant of the same State with themselves.
I would interpret this to mean that an elector could not have voted for the same person twice. I would interpret this to mean that an electorwas required to vote for two distinct persons.
As for whether it was generally accepted that the Vice President merely acted as President upon the death of the President rather than actually becoming President, here is an interesting article:
http://www.suite101.com/article.cfm/presidents_and_first_ladies/31466While researching this I found another interesting tidbit that Tyler was the first President to have a veto overridden.
One thing I do not find in the Constitution at all is something that says when a VP becomes President, his term lasts until the end of the person whom he took over for. Article II, Section 1, Clause 1 says the term of office for a President (and Vice President) is 4 years. So if a VP becomes President, you could argue that he gets his own 4 years.