We had Charles Neivel (I have a bad feeling I am spelling that wrong :-( ) [one of the famous Neivel jazz brothers, who played with all the grandfathers of Jazz] come and do a concert with a local jazz group and he even played a song with my school's jazz band. Local towns' cultural concils found the guy living
in one of the local towns and asked him if he would do it, they all chipped in the $ to hire the band, and he dontated his time and talent. Donations were taken at the door as the main fundraising part of the event, with the funds going to the school band department.
It wasnt actally a donation, but... I hope you are sucessful!
(actually, I live in such a rural back woods place, there are lots of actors and famous people with houses back in the woods arround here, but they really really try to stay in the shadows when therey are here b/c they dont want the reporters following them up here, so they are generaly unwilling to help with anything like you are asking about, but if you can get friendly with someone like that in your area...... (we MIGHT get someone VERY famous to do a concert for a NHS fundraser b/c one kid on NHS worked at a small breakfast place where this guy came every morning, and they talked a bunch..... (sorry, I cant tell you who, at least untill after the concert if it happens or more details are settled))