Our partner company had developed unique solution for Non NFC device make NFC enable phone(smartphone). Depends on the device design it seems most of phones fit this solution.
See following picture how it works.
See also install this microSD NFC and antenna module inside the Galaxy S2
So physically seems OK and then we need to develop the application software. Fortunately device and OS independent library and middle-ware is ready..so only application need to be developed.