We'll see! A lot of the things I had planned for v2.0 ended up being incorporated into the existing version "just because" but I do have tentative plans for creating a DIY 5-axis with accompanying full 3D CAM, with the goal of making CNC almost as easy as 3D printing. I also have other projects I'd like to do too so only time will tell :)
Once this project will become more popular, I think you will have enough income to dedicate only to programming this wonderful software. I discovered this project by mistake, was just a short mention into a forum, nowhere else I found references before. Definitely this project needs more marketing because have great potential.
I also intend to build a CNC machine with a 4th rotating axis (wood lathe) and the main head to be 5axis driven. Maybe my first machine will be only 3axis and the 4th for lathe, but second one certainly will be a 5axis one. If you need 5axis algorithms you can check the http://www.5axismaker.com project. It is a Rhino-Grasshopper definition that can generate 5axis gcode for CNC machines.
There might be a way that you can get PixelCNC to output G-code for a 4th axis by creating a custom post processor and doing some trickery with changing the Y axis to the rotation. Using the scaling factor you can map the Y dimension of the project to 360 degrees. So if you make a project that's 6 inches long in the Y dimension you could set a scaling factor to 6.0 for the Y dimension and change the register label in the post from Y to A (IIRC that's how you specify 4th axis angle?). I think it could be done, I'd be interested to find out if someone can pull it off.
I've already been working on PixelCNC pretty much full time for about 2.5 years now and my goal is to get it to the point that I originally envisioned, at which point it will enter beta phase and I will switch gears to PR/promotion/marketing mode. The goal is to expand it into a full income by the summer time. We'll see! Thanks for the feedback :)