An idea that has been floated (by me, at least) is to allow full-screen play with a letterboxed 800x600 game view, so the HUD can be moved outside of the actual game view.

But this is an area where JJ2's archaic nature really shows - it's not made to deal with as many pixels as the higher resolutions have and this makes increasing max resolution a complicated affair. And given the fact that the gameplay resolution is unlikely to ever move beyond 800x600, it's probably not something we'll see anytime soon.