Props to Lester for the idea of using an LCD screen for the background; it's a hell of a lot more convenient than setting up a diorama. I'll be using my own photographs though, partly out of respect for the copyrights of other photographers on the Net, but mostly because it'd make a more interesting challenge to create my own set of stock photos.
Total time for setup and experimentation:
a reasonably large LCD screen for the background
a clamped desktop lamp for lighting
a sheet of paper as diffuser
a stack of books and my everyday black hat as the elevated base for the figurine