The most recent judicial decision to reach the merits of the ACA's constitutionality was that of Judge Gladys Kessler (D.D.C.) in Mead v. Holder, which held that the minimum essential coverage requirement is within Congress's power to regulate interstate commerce. Judge Kessler handed down her decision eight days ago, February 22.
The plaintiff-appellants (Margaret Peggy Lee Mead et al.) have since filed their notice of appeal. And yesterday they filed a petition in the Court of Appeals for the District of Columbia, pursuant to Federal Rule of Appellate Procedure 35, seeking initial review by an en banc panel (rather than the standard three-judge panel). (You might recall that the plaintiff-appellants in Baldwin v. Sebelius filed a similar petition in the Ninth Circuit a few weeks ago.)
The D.C. Circuit docket number for the case is 11-5047. And you can access the appellants' petition for initial hearing en banc here.