Mickeymac87,
No but a belt holster that accomplishes what I think you want. It only runs a little bit lower than a standard belt holster, but offset from belt to get it out of the way of pack waist belt. I got it to carry a handgun with me bowhunting.
As you know, pack waist belts and shoulder straps can interfere with normal belt holster carry and shoulder rigs. My packs have pockets etc on the belt so there was no real good place to put it on the pack waist band itself except in the front with appendix carry, which I did not care for while hiking. Other suggestions were chest rigs, but I have my binos there.
So the holster I used, and which fit the M&P Pro CORE with an optic, is the Comp-Tac International. To achieve this you want it mounted in the "drop offset" configuration (there are a lot of choices). This also works very well when you are wearing a jacket, a pack and holster/gun are all outside the jacket to deploy quickly. It rides very stable there and has good retention (Kydex fit to your gun). Also, this way if you drop your pack, you still have the gun with you.
I will attach a several photos. If you have questions, pm me.