Probably the easiest option is to have a
custom cel place paint some backgrounds for you.
That way, you can tell them what kind of scenery
you want for your cels. The custom cels I've 
seen from several places are REALLY nice, and 
are inexpensive. Here is the URL to Moonshine 
cels, a custom cel place:
http://members.aol.com/marievega/celpage.html

I hope that helps! ^_^
  -Mara