So why use a flash at all?
Why not some nice CP tungsten halogen? That is after all what "Colour Photography" lamps were made for!
- Or even some of the better LED fixtures. The Royal Wedding Dresses were shot using static full-spectrum LED lighting. (Not "White" or "RGB". Those do have odd colour casts.)
Perhaps I'm biased as I'm a lighting designer (flash kills lighting), but flash photography always looks shit to me.
If you don't flash, then you don't end up with overbright, washed out, high colour temp, patchy odd-looking skin that you have to spend a long time editing out.
If you don't flash, you can actually look at the model and see what they'll look like in the image.
While your eye has a much higher dynamic range than a film or digital camera, it's still easy to see what the camera will.
Modern digital and film simply doesn't need high light levels - in HDTV we dropped the lumens quite a long way, and we actually got better pictures that way.
(For a while the same light levels were kept, and ended up racking the iris almost as tight as it would go.)