For directorial only... that is, showing up with no crew, equipment, or hardware except for the two director's "must haves" (director's finder and baseball cap) we usually bill $175/hr.
I will say though that it's a very rare thing indeed, at least in this market, for a client to call and need a producer or director only. The call is almost always for a full production crew and equipment... director, producer, DP, lights/camera/sound/support and all the toys. I'd say it's been more than a year since we've even had an inquiry seeking director only. I'm sure it's different in other markets.
Fantastic Plastic Entertainment, Inc. fantasticplastic.com
I think in our market (Madison) a producer day rate is anywhere between $400 and $700 a day. For directing, it depends on the project, but for most B2B video projects I would say that $1000 a day or more is pretty high. Budgets these days are more like $800 a day for typical corporate video directing. I can see more for a regional TV spot with a higher profile and when the director is chosen for a particular skill.
Most corporate clients would be surprised to see $1000 a day for producing a corporate video, and equally surprised if the directing rate was more than that much. Again, depends on budget, profile of the piece and perhaps distribution.