Just wanted to mention another, alternative hand-drawn sketch opportunity that we actually prefer to the 'artist drawn' sketches.
If you go on the Disney Animation tour (or, alternatively, you can enter via the exit and skip the film and concept art areas)... you can take a free animation class where they teach you how to draw a Disney character. The CM instructing the class takes you through the process, step by step, making it very simple for even the 'artistically challenged' to draw their own pencil sketch. You then sign, date and get to keep your drawing to take home.
My DS did a fabulous sketch this year of his favorite character, Stitch. In the shop at the exit, they had some very nice frames that were the correct size for the sketches (c. $30), so I purchased one and framed DS's drawing on the spot. It's the most special Disney souvie I have ever brought home from WDW... and means so much more to me than a stock drawing done by someone that I do not even know.