A while back, a approved form 1 under trust, was approved for MG. They retracted it. What happened since? Is there a thread that updates the situation?

You need to have a truckload of patience.

http://www.ar15.com/forums/t_1_5/1624460_ATF_approved_post_1986_machine_guns_for_NFA_trusts__legal_action_pending__updated_9_18_14.html

There was a case in 1991 that someone sued, won, but then went to the appeals court, where the justices ruled in favor of the government. The man appealed to the US Supreme Court, and the court refused to hear it. Turned the Appeals Court ruling into Case Law.

I bet they use the "Case Law" against any suit and dismiss the case.

A ruling from a District Court (federal trial-level court) is case law.  So is a ruling from a Court of Appeals--it's binding in a broader area, thoughout the circuit covered by that court.  So is a ruling by the Supreme Court; it's binding nationwide.  The Supreme Court's refusal to hear a case does not give it any more weight or validity than if they'd never been asked to hear it in the first place.

The appeals court's ruling was case law when they made it, and it remained case law after the Supreme Court declined to hear it.  It was binding only within that court's circuit when it was made, and it remains such after the Supreme Court denied cert.  It is not binding authority in any other part of the country.

This is a technical forum. Please post any comments in the linked thread above.