I don't have access to my reference material right now, but I believe www.dawsonprecision.com is the web address for info on a rail they attach to the dust cover of a 1911 pistol. Also GGG of Tucson, AZ can install a rail (sorry, I do not have their web address with me).
You can mount a Surefire Nitrolon, or Insight Technologies M3/M6 with a dustcover mounted rail, such as that offered by Dawson Precision. If you want to forgo attaching a semi-permanent mount on your pistol, you can opt for the Surefire Classic Weaponligh 610R system for brilliant 6V light. You can order from Surefire.com, or drop us a note for a quote on a special order. If you are looking for a duty holster, Safariland makes an excellent SLS holster for the 1911 with the 610R. HTH!
SKD Tactical, Inc. www.skdtac.com
Your source for hard-core, no-bs gear.
I use a 6V Surefire on my Sig P226 and I really liked it. I too am looking to mount a Surefire on my .45. I like the Nitrolen model for price/durability, I am just waiting for Safariland to make a tact. Holster for it.
As for the M3, I have the original from Insight technology which I carried on my G-35 on dutyand have never had a problem with it. I know of some guys they have had some problems with loose connections with the Streamlight model but overall they are satisfied with it. I looked at the Dawson Mount but I didnt want to permanently alter my .45. I saw where Wilson is makeing a CQB with a light rail built in now.