Tournament Idea: Reverse Modern?

Hey guys!
  I want everyone's input on an idea I had for our next tournament: Reverse Modern. One of our players suggested something about playing JUST older cards but had it restricted all the way to Alpha/Beta and having to use Alpha/Beta versions of cards. Well, that's not only extremely limiting but it depends on what Alpha/Beta you can get without spending an arm and a leg.

  However, I liked the idea: Take cards not "from X year onward" but "from X year backward".

  The trouble I'd have is, how far back would we want to go for this "Reverse Modern"?

  Here's the idea: Take all the sets from 19XX on back and those are the only cards allowed. To make playing easier, you may use current versions of cards that were allowed back then (so for example, you don't have to have an Antiquities Mishra's Factory in order to play it. You can use the ones from Duel Decks: Elspeth vs. Tezzeret).

  We could also give bonuses for using all/almost all older versions: For example, if your deck is entirely black border without using newer-framed cards (Mirrodin and 8th Edition onward, or the current frames) or alterations (coloring in the white border, for example), you get +10 life or +1 to maximum hand size or some bonus.

  What does everyone think? What would you suggest be the cutoff for "Reverse Modern" (either by year or by block/Core Set).