Well, on that topic, I have a few thoughts. (You shouldn't be surprised.

The pursuit of a more-robust (and thus, more profitable) postseason is a worthy goal, but doesn't even require any extension of the current calendar. 2011 is already set, of course, so 2012 will be the next opportunity to do so.
My suspicion is that Selig might be (who actually knows?) limiting his scope to the traditional American in-the-box thinking of organizing the calendar and the postseason. But other major organizers of sports around the world, such as Olympic organizers and European soccer leagues, have seen the wisdom of using pool play and promotion/relegation systems. While it would be anathema to adopt those in any pure form, there are principles of both that would work well under this structure:
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REGULAR SEASON
- 108 intraleague only games that run through July 31.
- Top 10 teams from each league graduate to the next stage, what I'll temporarily call the August Pool for want of a catchier term... while the bottom six NL teams and bottom four AL teams begin competition with each other over last two months (54 games) for the Bronze Cap.
- Bears mentioning that 108 -- divisible by 2, 3, and 4 -- is an optimal number of games mathematically, which makes scheduling for a 16-team and 14-team league particularly flexible.
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AUGUST POOL
- 30 intraleague only games... Top teams in each league play a three-game series against each of the other teams in their league, plus one additional series against its opposite rank (e.g., one plays 10 an extra series, two plays nine, three plays eight and so on)...
- Top five teams from each league graduate to the September Pool, while the bottom five of each (10 total) vie against each other for the Silver Cap.
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SEPTEMBER POOL
- 24 intraleague only games... Top teams play a three-game series against each of the other teams in their league home-and-home... given the odd number (5) of teams, each team gets two three-day breaks during the month, and otherwise plays every day.
- Top two teams for each league advance to the American or National League Championship, with home field advantage going to the better September Pool record
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PLAYOFFS (League Championship Series)
- Expands to best 5-of-9 games, having dispensed with any need for a Division Series (due to the heightened intensity of the entire previous two months).
- Gains a significantly higher likelihood to keep the postseason contained to October year-in-year-out
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WORLD SERIES
- Expands, also, to best 5-of-9 games (for which, by the way, there is some historical precedent)
- Addition of a new predetermined neutral-site Game 1 so that neither league obtains (what has always been a warrant-less and unfair) home-field advantage
- Winner not only wins the trophy, but wins the Golden Cap, which means that, the following season, that team exclusively gets to wear a golden-billed cap that serves as an every-game reminder to the opposition and those watching that they are the game's reigning champion.
- By the way... the winners of the Silver Cap and Bronze Cap seasons get similar treatment (silver and bronze colored bills), and going back to where this concept began... the greatest asset of this is that it keeps every team playing for something practically through the entire season... and that, then, translates into some degree of greater interest at the ticket window and among advertisers than what baseball currently enjoys, i.e., an enhanced, if not maximized, revenue stream.
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So, there ya go, Bud.
No charge, my friend. Just a public acknowledgment that an anonymous fan contributed the concept is enough for me.