Texas-based chains Mr. Gatti’s and Gigi’s Cupcakes, owned by an interlocking group of investment firms, filed for Chapter 11 bankruptcy protection Jan. 4. Gigi’s was reported to have about 100 units, the venerable Mr. Gatti’s 76, mostly franchised. And last week, seven units of Seattle-based Blue C Sushi, owned by Seattle’s Madison Holdings restaurant company,…