One of my favorite light mounts is the HSP THORNTAIL Adaptive Light Mount which is made by Impact Weapons Components.  The THORNTAIL extends the light out beyond the end of the rail allowing for more realestate for your hands.  The first version uses different size rings to accommodate different flashlights.  Haley Strategic Partners and Impact Weapons Components have just released a picture of their newest version which is designed to be used with the SureFire Millennium series of Weapon Lights. 

The HSP THORNTAIL Adaptive Offset Light Mount is designed to be used with Millenium M951, M952, M961, M962 & M620 Weaponlights.  Keep your eye on for availability and pricing!