jbadams and David Ga11agher already pointed out the important things so I don't have much to say about the possibility
of these projects.
But I want to add one point: don't focus to much on the genre! The genre says some kind of nothing about the final game as mentioned in one of the Extra Credits Episodes (I'm not sure about which one it was, but you could have a look at Extra Credits: Combining Genres
). In an other episode if not the same they mentioned the difference between genres in film and literature. When you see a movies genre you know quite exactly if the movie is interesting for you while game genres focus on a specific mechanic or the point of view (_first person_ _shooter_, _plattformer_ (btw: in other locations referred to as "Jump'n'Run"s) and so on). I'll have a look fore the right EC video later...
As mentioned: the content will take a lot of time so you should not make a game which depends on
much content. Shooter, RPGs and adventures (also action adventures) need much content to some extent. (Local) multiplayer games doesn't need much content or much mechanics in general to be very enjoyable. You may could have a look at these games. ;)
And don't forget about the sound and music!
Oh and by the way: Zelda is not an RPG, it's an action adventure! (Except for Zelda II maybe...)