After many mistakes, here is another test version of crvFillet for curves that actually works.
It uses Karsten's code modified, with Michaels fillet/Chamfer code.

Nothing has been done for a point selection mask or boolean yet.
It is just a test version, with very limited testing.

I figure that a Chamfer version would be very similar...
My programming play time is limited by too many other projects, and too little quality clear thinking time:-)

- Brian

p.s., place crvFillet.js in the Extensions folder of nodeeditor. (I use the AppData structure)
The test node will show up in the Curves2 menu.