These local "artists" are all along Michigan Avenue and State Street preying on unsuspecting tourists to create a charicature with a famous Chicago landmark in the background. For $10, you'll be wishing that you didn't spend 15 minutes with these entrepreneurs.
Unique Suggestions Just don't do it. There's nothing good that comes from it.
Fun Alternatives If you want something famous in the background with you in the foreground, the John Hancock Tower, as cheesy as it seems, has a reasonably nice skyscraper view where you can stand as if washing the windows. The north side and lake is in the background and this picture can be taken day or night with your own camera.