If you want the small mags, your best bet is the Kel-Tec site. They also have 12rd mags that are the same size as the 10rd.
In case you weren't aware, the S&W 9mm X59 series 15rd (17rd by Mec Gar) mags also fit the P-11. Of course they stick out, but for a reload or range mag, so what...