Although I originally asked artists for portraits of various people as cowboys, the art that I was sent really didn't work for me. At first I thought that it was a matter of style, then a few days ago I realised that the whole concept wasn't really working for me, even the photo-manips I started out with. Entirely my fault, of course, but unfortunately that's the way things happen sometimes.
What I've decided to do is revert to something I used in some of the play-tests; caricatures from a French site that has hundreds of them, http://www.magixl.com. For example, here's the illustration I'm going to use for the Elvis character record. The guy who runs the site has agreed to let me use them on the same terms as I was offering before; a pound to charity for each picture I use.
Since the artists who sent me work have obviously gone to a lot of trouble I'm also donating a pound to charity for each picture I was sent, even though I won't be using them. Adding in the payment for the cover (Aaron Williams) and caricatures, I think that the final total will probably be £25-30, since I'll want a few other pictures for NPCs.
Anyway, many thanks to those who participated, and my apologies that in the end I decided not to go with your work.