Well, I've looked at the javascript array capability and I believe an interface plugin would be feasible. Basically expose all javascript array capabilities as well as instantiate the array itself. Perhaps there'd need to be two plugins, one global (for arrays in expressions) and one instance-based (arrays as objects).
Alas, I have no experience in js development, so I'm only going to develop a very rudimentary array object plugin. All this Construct 2 extensibility is still difficult to figure out, however, so I can't promise anything.