Steve Bissette, a comics artist who also writes and publishes, has posted a great piece on issues surrounding collaborating on a graphic novel.
The piece is relevant because the requests that Bissette is addressing are similar to those that I regularly address as the coordinator of Sheridan College's animation program. I am constantly fielding phone calls and emails requesting that students create films for individuals and organizations. As Bissette points out, like it or not, drawing takes longer than writing. And animating most certainly takes longer than writing.
My first question when I get these requests is to ask if this is a paying project. Most times it isn't. In that case, my response is that we have a highly structured curriculum and we're not able to accommodate the request. If the job is paying, I try to connect a recent graduate with the project.
I don't doubt that many animation artists get requests like this. I remember somebody who wanted an animation done for her daughter's birthday party with a caricature of the mother as the main character. I think the fee on that was as high as $100, but when I quoted industry rates, that ended the discussion quickly.
People generally don't understand how labour intensive drawing and animating are. They also assume, as Bissette points out, that artists are devoid of ideas, just sitting around waiting for somebody to give them one. The problem is never finding an idea, it's finding the time and money to work on an idea.
Bissette raises a lot of issues concerning ownership, royalties, etc. which are food for thought for anybody who is hired to collaborate, as opposed to simply being hired to execute. While the issues surrounding graphic novels and animation don't match exactly, there are enough in common to make the piece worth reading.