I just wanted to say a couple things: first, what a fantastic idea! This is one of those things that I wish I had thought of a little earlier, as it's becoming very last minute at the moment. What a great idea giving a gift of art!
Second, I wanted to really give Claudio a positive recommendation as someone to work with. I had a friend publishing his first book (nothing to do with RPGs) and he needed a cover. I had seen Claudio's work and was familiar with his posting history on ENWorld, so I sent my friend his way. He was fantastic to work with and did a great cover.
It's actually been my experience that most gaming artists are very easy to work with: I've commissioned work from several of the folks who've drawn for books I've liked, and in each case I've been very pleasantly surprised with the cost and how responsive they've been.
--Steve