Tony Fadell recently appeared on The Verge's On The Verge talk show/web series, and he shared a tidbit about early versions of the iPhone, which he worked on as Senior VP of the iPod division at Apple back in 2006. The Verge says that Apple "seriously considered" a hardware keyboard for the original iPhone, according to Fadell, but if you watch the clip itself, you can see that Fadell confirms Apple never made a keyboard for it. The issue was "definitely discussed," he says, but nothing was ever made into a prototype.
Fadell also says there were three different "gestations" of the iPhone during development -- first an iPod plus phone, then an actual "i-Phone," and then "there was the next generation iPhone, and that's the one that shipped," he says. Fadell says they did work with the iPod's original clickwheel on iPhone hardware, which reminds me of those old fake mockups that designers put together before the iPhone was announced.
At any rate, says Fadell, Apple was open to anything. "Sometimes you have to try things in order to throw it away," he says. Given Apple's history since the introduction of the iPhone, we'd say it was all worth it.