Is there any way to add a feature to allow the customer to upload a file during their checkout?

For example, if my site is for an image modification service, the customer will select the service they want to purchase, check-out, and upload their original image during the checkout process or immediately after.

I know they can just "email it to me" after they pay for the service, but that is no good! I need the file to be uploaded as soon as they pay. Also, it would be great if the files could be associated with their account.

Is there any way to do this? Or would someone be interested in making this work?

Please please please help. Thanks!