J.P.
If you go to where Santa is set up in a mall, it would probably make a great background! I took a picture of a little girl last year while we were waiting in line, and it turned out great with the trees and ornaments and fake snow and fence behind her! You could probably find an area you could fit the family and maybe have your photographer photoshop any areas that show the carpet or parts of the mall so it looks nice. Other than that, I don't have much for ideas!