Just a reminder that TourGuide Mike - one of this site's sponsors - offers these services, as well.
Check out his website. One thing that he offers that (supposedly) Disney does "not," is that you can "meet" your guide long before your trip, and exchange ideas, special requests, preferences, etc BEFORE your trip... so that they can "get to know you."
He feels that this is a really valuable service... so that no time is wasted during precious "park time."
DISCLAIMER - I have no affiliation with TourGuide Mike... never used him... don't know anyone who HAS. (Although William Shatner left a nice referral on his website!)
...I just spent some time reading through his website yesterday, and it sounded pretty neat.
His rates were slightly less than Disney's, but not much.
FWIW....