In my research I have not been able to find an Arts Festival Planning site that is comparable to what I am planning. What I have found are sites with pieces of content such as:
Festivals and Events with a manual for promoting and implementing a nature festival
Festival and Event Planning with tips, forums and calendars
Here are some sites with features that I like and want to emulate in my Arts Festival Planning site:
One Good Thing is clean, have great visuals and easy to find and/or search information.
A couple research oriented sites MFAH and London Lives have features that demonstrate good cataloging and archives.
Voguepedia and Vogue Archives are favorites for simplicity.
The Art of the Festival 
Hello Mary! Have you seen http://artoffestivals.com/? It looks like it’s based out of England, but covers some material similar to what you’re doing here.
I had not seen the site, thanks.