Looks like Konami has a rival in the collectible baseball card game business - Bandai is releasing a set called Owners League. I think it's a 240 card set (which probably means 20 cards per team). I can't find anything "official" from Bandai, just what I've seen on a couple website selling cards.
I just realized that Jason had sent me a link to the Owners League official website a couple months ago. It looks like there may be two sets - a 240 card set and a 60 card "Owner's League Draft" set.