A friend and I were having this exact discussion. I was looking just like you for something not obvious. I have an older Marmot (man purse as my wife calls it) fanny pack that looks like any other. I also like the mountain smith stuff. I considered installing a kydex holster or one of the Velcro types from Maxpedition into our diaper bag (Arc Teryx pack that has been serving us for nearly a decade). I think you’re on the right track, I like the durability associated with the tac stuff but LEO's aren't the only folks who recognize that kind of thing. I prefer to be part of the scenery not the lone pine in the middle of the field.
So in short find a civilian pack you like (love Timbuk2 packs) and rivet in some Velcro or a thin holster if you like.
Side note: when I see maxpedition packs (I have a couple) I think gun.
I warned you, but did you listen to me? Oh, no, you knew it all, didn’t you? Oh, it’s just a harmless little bunny, isn’t it? Well, it’s always the same. I always tell them