Wow, lots to answer.
1. Yes, TK instruments
2. Again, not the Stick
3. Yes, if anyone has a source for Parker half rounds, please reply.
4. Bending to radius not important, as fretboard will be flat. I love classical necks.
5. I had no idea there were other threads on "bar frets", but I'm talking about rods, not bars.
As for why, rods are easily available bigger than any frets. For example, Yngwie sig guitars use 6100's and a scalloped fretboard. The same vertical distance from fret top to fingerboard wood could be accomplished with a taller fret, but since frets that tall aren't made, in come the rods. And a stainless rod that big should last a long time.