Suggestions for Full Length Cardboard Cutouts

I'm the graphic designer for a credit union and we need help directing the members in the various branches. We're trying out the idea of using a full length cardboard cut out of a person to do it (holding a banner with text for direction). I'm not completely sold on the idea, but my boss wants to give it a shot.

Anyway, I'm having a problem finding stock images of people that are big enough to blow up full size, am I missing something? (Also, not totally sure this is the correct place to post such a question.) The biggest ones are about an inch and a half. I realize at full size 5-6 foot, they aren't going to be super crisp, but I don't want them to be TERRIBLE. Any ideas..?? Thanks!

I should suggest You to look for some stock photos, You can try sxc.hu for free high quality photos or istockphoto.com - for a little prize, but really huge size.

And if the cardboard is so big, You also could consider thinking about impersonal people shapes maybe? Shapes can be vector based and always will look lovely.

We have a subscription to istockphoto.com, so no need to worry about money. We're certainly willing to put down the bucks for it, I just can't find a file that will be big enough. I just want to make sure I'm not missing something -- I know the file doesn't need to be 6 feet tall, because you'll be looking at this from a distance, but how big does it need to be? Just a bit frustrating. Thank you for your suggestions, I do plan on checking out the sites you posted. Has anyone ever created a cardboard cut out like this before?

Would it not just be easier to get the background you want no background then just take your own picture. I mean you've put so much time into finding that perfect stock photo when you could have taken your own by then.