The circuits are now split 3/1, with the majority finding a waiver of sovereign immunity under Section 544(b)(1) for lawsuits by a trustee based on claims that an actual creditor could not have brought outside of bankruptcy.
The Supreme Court resolved a split of circuits in an opinion that could give support to the notion that arbitration agreements are not enforceable in bankruptcy.
It appears as though the Supreme Court will decide Lac du Flambeau based entirely on textual analysis of Section 106(a), which does not explicitly abrogate sovereign immunity as to Native American tribes.