Thanks for sharing these links! I did take a brief look at Selenium, but due to my lack of familiarity with it and no mention on how to save the full page in html (instead of screenshot) I moved quickly to writing this version using xdotool. I agree this approach is more clunky and perhaps less likely to work across different platforms (than say Selenium/CasperJS), but it finally served the purpose for me (Ubuntu 12.04, GNOME, Chrome) by letting me download a bunch of communities. :)

Good luck with your CasperJS approach, and I would love to learn from it if you wish to share the code later.