Just starting to get into Vim and facing the classic escape problem. I'm thinking binding CapsLock to be control when used with another key, and escape when released without pressing anything else would be a great solution. However, I don't want to do that if escape is used in some important key combinations.
If, when you write "combination", you are referring to when two keys are pressed simultaneously (sometimes also called "chords" by analogy with musical terminology), then Escape cannot be used in such combinations and thus you're safe to rebind your Caps Lock key in this way.
Note that hundreds* of other Vim users (including me) already do this with no ill effect other than the fact that it becomes more difficult to use other people's computers once you get used to it. It's for this latter reason that I'm not sure if I'd recommend you do this, but it's totally fine to do so, at least as far as Vim is concerned.
* Thousands? Millions?!?