No its not on the market (4.3 hasnt been released yet), but the 4.3 jellybean build of the samsung galaxy s4 GE was leaked, and the camera, wallpapers, and bootanimation have been floating around the web.
You can just install it like any sideloaded application
I'll take one as well.
It's one of those features I've used a lot on my Gnex and couldn't live without it on my S3.
PS, FWIW, sideloading the apk on my Gnex worked fine on AOKP. But, I imagine being a Nexus makes a big difference.