Has anyone ever been prescribed both? I was on Ritalin for a couple years and found it helped my short term memory but didn't help my focus a whole lot. My Psych swapped my to Adderall regular a week ago and it really helps my focus but not my short term memory. Was wondering if a half dose of each would accomplish both tasks. If I have to make a choice it would be for the Adderall. I can work around short term memory (post its, notepad, list, Palm, etc) better than I can the focusing and staying on task.

Some people have taken both, but it'd be rare. Have you taken Ritalin lately? Nothing I've read suggests that it helps memory - we ADDers have less short term memory than others and there is not a lot you can do about it. I'm not sure why you would perceive that ritalin helps with that and that Adderall doesn't?
You could ask your Psych about it - I'm thinking that he/she will have issues with it, but who knows? No safety reason I know of that prevents you from taking them both at the same time, in half doses. I don't know if they would be fully effective that way - some drugs need a certain level in the blood stream before they start to work fully.