I have seen those, I think a couple of the MI ones would work.
Here is what my setup looks like. It has the ACE Pig nose, and a locking nut. The Pig nose and the nut are the same outside diameter.
Using most (or maybe all) looks like it would have to sit between the nut and the brace, which would slide the brace back a little, which it fine.....I just don't know what the new gap between the front of the mount and the back of the receiver would look like, or if it would make an area that things would want to grab onto. I am not going to battle or anything....haha, so mostly just looks I guess.
I have the style of mount that has the low profile QD socket built right into the locking plate on my AR pistols, and like that because I can use my Magpul sling as a single point, or add and use a front mount if I want to use it as a 2 point sling.
I saw someone that drilled a hole in the side near the back of the receiver and uses one of the QD mounts that sit just a little above flush with a nut on the back. That would be great, just don;t know if I want to drill another hole in the receiver....I guess I already added 2 in the back.
I am just thinking out loud here........looking for ideas that i maybe haven't thought of yet.