I like the idea for a Challenge. There is a common concept called V-caches (virtual, wherigo webcam), which are ignored in many Challenges. So an alternative could be to exclude those if they doesn't fit your location. I am also not sure if all types exists in all sizes. For example, a virtual cache can't really be a small, since it doesn't have a container.
I haven't checked how I do myself with a T/S-matrix yet. But I will look into it I think. But first I need to research which types has all the sizes.
PS! I have moved this question out from the Checker request category since it's not a checker request and more a question of peoples opinions. Our plan is to keep the checker request category clean enough, so that those who write checkers can look in it and find what more checkers the users want.