One thing for sure, Ross does listen to it's customers!  The M11DS belt Holster is a 1st cousin of the M4 but with the following features: 

A thumbreak snap was added for those who want or are required to have a thumbreak on their duty handguns.  The belt slot in back was changed to a 2-way allowing the M11DS to be used as a hip holster on the gun-hand side, or as a crossdraw holster on the support side.  Crossdraw is a very effective carry style when seated (car or desk).

The M11DS Belt Holster is a HIGH-RIDE holster and features a molded-fit to the exact handgun with a CLOSED BOTTOM to keep clothing fur out of your muzzle.  This feature is found on the best,  custom made holsters, except with the Ross Holster, if your gun model is not in stock you will only have to wait about 4 weeks. 

As an added feature, as if delivery, price and molded custom fit weren't enough, ALL the Ross Holsters are SUEDE LEATHER-LINED and you don't pay extra; it's just the way they do it at Ross.  Available in Black or Tan, Right or Left Hand.