Tier 1 Concealed out of Utah can make one out of whatever plastic is being used these days (actual 'kydex' is going the way of the dodo apparently).
I recently picked up an OWB from them for my M&P w/ light and red dot. Holster is good quality, and service was relatively quick (couple weeks) for a custom holster. They have a number of features that you can specifiy, and do list railed Commander length 1911s as a configuration.
I carried a Kimber TLE Pro for a while a long time back and it was very difficult to find holsters for it. Other than plastic, I don't think that has changed much.
Slim-Line IWB Tuckable Holster (MTR). This holster can be ordered for no rail or rail. The gun is a SA Range Officer Champion. I have several MTR IWB holsters and have no complaints