The decision on the 2012 IndyCar was supposed to be made by today, June 30. IndyCar CEO Randy Bernard has said recently that the decision might be made by today, but the announcement won't be for a week or two.
UPDATE: Indy Star's Curt Cavin reported Wednesday afternoon the announcement will be on July 14.
The contenders are Dallara, DeltaWing, Swift, BAT and Lola. Check many posts on them all here.
Hope springs eternal for a multiple-chassis ruling, but several chassis makers have said unless they can have the economy of scale of supplying the whole field, they can't afford to offer a chassis at all.