Hey, I've been working on a few of these for some advertising we are doing at the moment. I did them on photoshop, didnt take too long. Just cut out the silhouette and then do a colour layer on top. You can get some good results, some of the images need smoothing up a bit but it depends how bothered you are to work on them.
If you want I can send you some of them. I cant figure out how to show images on here.