My assorted carry holsters for the XDm....
The leather thumb-break is what i carried the Glock 29 in. It's a De Santis 001E8, which is made for Glocks, but the XDm is so close in size to the 29 that it fits this holster. It was tight at first but has loosened up in time. The button snaps in place and the fit is snug. Not a bad choice if a XDm specific thumb-break is not available.
I love the Black Scorpion for IWB (usually worn at 2 or 4 oclock position). It's very light and comfortable.
The Kenai chest holster is by far my favorite for woods carry. Been carrying the G40 and the S&W 610-2 with it for years...bought another shell for the XDm.