Unique question about excel and touch screen signatures

Ok, so I work for a school district in San Diego and I have been tasked with piloting a tablet next year at my site. Now I know some of this might be better suited for a tablet forum, but I wanted to find out if the functionality was in excel for one of the things they've asked me to try and come up with.

Each day we have to sign in each student and the parents want to sign them out. Is there a way in excel to make it so that I can create a sign-in/out spreadsheet with excel were the 'signatures" cell could easily be filled in on a touch screen and have it save the actual signature to the cell? Designing the spreadsheet itself is easy, but I've never attempted anything like this before.

Ideally I would like to have it so Jonny walks in, checks in with the staff who scrolls to his name, selects the cell with a stylus, and a window or something pops up where they can just put their signature, and it will show up in the cell as their signature. Then when Jonny's mom comes to pick him up, she scrolls down to his name, selects the sign out cell, signs, and it saves her signature as well.

Any help would be greatly appreciated.

Thank you.

You can do this in google docs quite easily, you can open a panel for drawing, scrawl on it and save it directly into the worksheet.