Philly.com: Toilet Innovations, From Both Sides Now
Don't take this the wrong way, but I have had lots of experience with toilets over the years.
I've written 235 stories about them for the Inquirer alone since 1989, did a piece on dual flush for Popular Science in 2005, and included a chapter on toilets in each of my books, albeit as part of the bathroom.
I also brought toilets to the Home Matters show for an episode when I was "the Gadgeteer."
There was an article that took a toilet apart, interviewing plumbers and manufacturers who explained how they worked.