It doesn't have the form factor of the iPhone - it's quite a bit thicker, if only slightly heavier - but for combining a mobile phone with a portable web browser, can I bring people's attention to the Toshiba Portege G900?
I've played with mine beside an iPhone (surfing via 802.11b), and, while not as fast or as slick (thanks, presumably, to Windows Mobile 6), the screen and integrated keyboard (and 3G, and Bluetooth) ensured that I don't have iPhone envy. Reading a web page at full size on the 800x480 screen (same as the Nokia internet tablets, but only 3") is preferable to the iPhone's poke-pinch-and-slide interface, and you don't get smears all over the screen.
It's had some stability problems (largely fixed by the community with some registry pokes, depending on what you're doing with it), it's a bit quiet, and it's by no means as responsive as the iPhone - but for surfing in the field I'm happy with my solution. It's miles ahead of the P910i I had before, or any QVGA display.
I've not really used its media player, so I can't vouch for the iPod abilities (I'd rather save my phone batteries for phone calls anyway), but for the most-pushed iPhone feature, the "mobile internet", it's a real competitor for the iPhone, even if it doesn't look like one. Maybe I'm enough of a geek to consider the fashion status of the iPhone to be irrelevant; YMMV.
(I have no connection with Toshiba, and no vested interest other than getting enough people to buy G900s to persuade Toshiba to give better customer service, btw.)