I've gotten some good feedback on my single-page AdSense site articles, with people like Stuart Drew really taking things to heart. I like Stu's acronym for the “single-page ugly site” which he renames the “one-page ugly site” or OPUS for short. But then again, Bloom County featuring Opus the penguin is one of my favorite comic strips…
Here's another piece of advice for you: if you have an OPUS like No debt is good, avoid using link units on them. I've stated before how horizontal link units can add to the bottom line on most sites, but I think that they're wasted on single-page sites. The point of a single-page site, after all, is to force the visitor to exit either by pressing the back button or by clicking one of the ad links. With link units you reduce the probability that they'll click a money-making link. So I would avoid them.
By the way, pages that have no external links are not as uncommon as you think. Take a look at this page on the history of MS-DOS. No links on it anywhere — to get out you have to use the back button.
Eric Giguere is the contextual advertising expert who wrote Make Easy Money with Google and Uncommon AdSense. You can read this blog by mail if it's more convenient for you, just send a blank email to memwg-blog@aweber.com to subscribe.