I expect Terry to stop by and tell you that some Totos will install in a rough in space under 11 inches. Or, do a quick search. He last gave that answer about a week ago.
If you haven't already installed that tile, you may want to reconsider. I would recommend you post your specifics at johnbridge.com, a tile forum that gives wonderful support to DIY'rs. Removing the ply may have left you with too weak a subfloor.