Seems to be a perfect merging of styles to me; a pad to keep the watch off your skin(Love that feature in cold weather) and the advantages of the pass through band of a Nato, less likely to lose the watch if breaking a pin, etc.. Not to mention the cool look of both styles 
All it would take would be the lower strap of the nato being made wide, in the curved shape of the average bund pad.
I’ve searched, and searched, and searched the ‘net, and all the watch forums, and have Never seen this done, or any mention of the theory.
I;ve done it by adding a existing bund pad to a canvas nato strap, it works great as intended, just ends a bit too bulky for my tastes, thus the though to just integrate the pad into the lower strap.
I have some thin leather on the way for making another leather Nato/5 Ring Zulu–since I can’t buy another like the one I have; the dealer no-longer stocks them–, I think I’m going to try it built like this.
I was able to find one a while back that was a one piece strap like a 2 or 3 ring Zulu, only in leather, run through a bund pad. Sort of a half step to what I want, and actually a lot simpler in design and execution…. But I still think it would look better with the pad area made into a layer, would do away with the offset and the loops on the end of the pad for the strap to go through, just a bit more compact I think..
Like this, only in one piece on the bottom, one material and no rivets obviously. 🙂
Alaskan, Adventurer, Engineer. 