I wanted to do Hunt's Mesa, but my guide (Tom Phillips) indicated that it is that to get good lighting, you pretty much have to make it an overnight trip.
For my wife and I the cost would have been $500 (it cost us $300 for sunrise/sunset day for me, and sunset for my wife-after 3pm).
He said that he and another photographer (can't remember the name), hold a workshop, where participants camp out at Hunt' Mesa, but i'm not sure when that is.
Not sure what kind of rate you would get from another guide, but one thing i found, was that while you may be able to get another guide, at a better rate, he may not know where the best light is, or take you out during ideal lighting conditions.
Tom also took me out to Teardrop arch as part of the full day cost, whereas, Danial's tour charged us an extra $45 each to go out there, since the arch is not actually in Monument valley.
The other advantage to going with Tom, is that you are in an enclosed vehichle, whereas Danial's tour, and most of the other tours I saw were in open vehicles (sort of like a pickup with 4 rows of seats in the back). This may not sound like a big deal, but it makes a big diff considering all of the dust when you are driving off-road with camera gear.
Prior to my tour with Tom Philips and Danial's tours, I had also asked Gouldings for a private tour, for the last day I was to be there, since there full day regular tour rate was around $65. But they said the smallest tour they do is groups of 4, unless you are willing to pay for 4 people (even if two are going). after seeing a couple of gouldings tours while i was out there, i'm glad i didint' book with them - they are not geared towards photographers at all.[/font]