Here is a picture of a quilt by Sharon Malec that could be modified to be a panther:
http://www.malec-designs.com/index.html
I'm pretty sure the pattern for that quilt is in this book of hers:
http://www.amazon.com/Dog-Lady-Goes-Wild/dp/0970349610
I have that book here somewhere, but not sure where. The technique she uses is different than any other I have seen, but really easy to do. The one thing you need is a little artistic sense in order to use fabrics correctly for shading. I think this would actually be harder for a panther than the tiger, because you would be working mostly with shades of black and gray. With the tiger, at least you have the natural contrast of orange and white.
If you are interested in this pattern, I will try to dig through my collection to find the book and verify this pattern is actually in the book.
What would be a *lot* easier for a raffle quilt would be finding a fabric panel with panthers on it. I tried looking for that too, but didn't find anything suitable. Maybe someone else could, though. You can always extend a panel with coordinating border fabrics.