In the original concept I wanted to do something like that, but right now that's on indefinite hold and I'd have to say "it's not planned, even though I'd like to do it". The reason is that thanks to the art and the way the game is sort of semi-open, semi-story based, it's very difficult to fit that in. We'd need a lot of extra art and it wouldn't be too practical.
If anything like that ever happens, it'll probably have to be through some kind of fancy time-jump story contrivance, but like I say it's currently not planned.