Crossbreed Holsters LLC has a new ankle holster in its line-up. The new ankle rigs were designed by the inestimable Mark Craighead and made in the USA. The holster has a calf support strap (so it doesn't slip down and start smacking the wearer's ankle) and sports a reinforced/padded ankle section for greater comfort. It also features a thumb break for retention during rigorous activity. The new holster (currently right hand only) will fit small to medium semi-autos like the LC9 and XDS. Note that it's a universal holster, so the XDS and a Kahr K will be a tighter fit than an LCP, though Crossbreed advises it will stretch to fit the latter with comfortable retention.
They are currently working on a larger size for smaller Glocks, S&W Shields and revolvers.
For those who never met Mr. Craighead: