Back to AR15.com forums, first post on page 45 last three photos are of a PT1911AR with light in a DIY OWB Kydex holster. You will have to read through a number of pages before that to get the details on how to make one, but everything is there.
Do it yourself Kydex.... - Page 45 - AR15.COM
This is not a hard holster to make. Another variation is to use leather for the backside of the holster (you don't need to form the leather, let the Kydex do the retention). I prefer leather rather than plastic against my body, it's just more comfortable. Forming the light/laser attachment is the tricky part as you need to make sure the pistol can still be drawn after forming.
Page 40 of the above thread and about 2/3 of the way down is a pictorial on making a Kydex specifically for a railed pistol with a light.