Nope- his business manager was quoted as saying that soba is too difficult and that Masa would not split his time away from Masa Sushi to create another sushi restaurant. He did hint that it would, however, involve "fish".
Although the owner retired, the original chef (i believe) is now working in 15 East and is solely responsible for the soba dishes there. However, the price is now twice or 3 times more expensive than Homura An's.