Moviefone blogged this earlier today, and it's EPIC. It might mostly be a video, but it's the closest I could find to anything Snape-related.
I can't directly put the video on here, but here's the link: http://blog.moviefone.com/2011/02/25/alan-rickman-villains-insults/
While he his a sarcastic badass, I must point out that Snape is NOT evil... well, he was. And he still sorta is, but that's just the 'hating James Potter' coming out. The good in him wins in the end...
But seriously, I think J.K. Rowling had Alan Rickman in mind when she wrote about Snape... can you actually imagine anyone else playing him? He already had the 'bad guy that's really just misunderstood' persona, a huge nose, and a voice like cold silk. And I could spend a LOT of time listing all the similarities and references to Snape and Alan Rickman's other characters, but I don't feel like it.
