Can the trebuchet launcher be installed on the stock ROM? Phone: Samsung Galaxy S4
Android: 4.2.2

Can the trebuchet launcher be installed on the stock ROM? 

I can't find the app on Google Play. Where could I get this?
Yes it can (with varying degrees of success)! I'm running it on my Prestigio 3350DUO (Android 4.2.2). But there is a problem with crashing on certain preferences (NumberPicker), so I cannot change number of screens or default screen, as well as number of docker icons/pages. Besides that, it works great - it's fast and stable and looks cool!