It has worked to an extent in football and basketball, so it's only natural that we try the same thing in baseball. Bear in mind that I only have 1 GU card for baseball, a 2003 Reggie Jackson that I just acquired a couple of weeks back. Everything else is base & inserts (parallels included).
NL East: I collect the Mets. Braves, Nationals, & Phillies are in limited supply, but I have plenty of Marlins. Also, I need to know if anyone's looking for Montreal Expos cards (before they moved to Washington). I have Expos cards from the 80's up through 2004, plus there are some 2005 cards that have the Expos instead of the Nationals.
NL Central: I have a limited supply of Pirates, but plenty of everyone else.
NL West: Everyone's in play.
AL East: Everyone's in play.
AL Central: Indians, Royals, Twins. Limited stock in White Sox & Tigers.
AL West: Everyone's in play.
Please be specific about what years you want, because I have cards dating all the way back to 1979.
I also have Mets cards dating back to 1971, which are part of my personal collection, but will listen to offers.