I do have a self propelled round baler mod released here called the AgriFlex, it is a modified Vermeer Zr5 with similar improvements as the ProBale plus it has a 3 point mount and can also cut and bale poplar and cotton.
A self propelled square baler will be a bit more work unless I just made the Agriflex spit out square bales which would look kind of funny. I will look into it 🙂