(A) Sounds like you're describing an LRU.

(B) You're talking to the wrong list here. Step 1 is for you to want this data structure for some actual reason (not just that you just learned about it, but that you have a real place to use it in your own code). Step 2 is for you to implement it in code. (Put it on GitHub or something.) Step 3 is to stop there, since once the code is available there's no reason to bother the Committee with it; but at least there's certainly no sense in bothering the Committee with it before steps 1 and 2 have happened.

(C) Have you looked at what you'd get by using Boost.MultiIndex?  (Search "boost multiindex lru" to find people already using it as an LRU.)

–Arthur