I'm not sure when it happened, but it looks like Yahoo! oneSearch has been updated with a beautiful new iPhone-friendly interface. You'll see it if you visit oneSearch on an iPhone (and only on an iPhone).
Unfortunately I have no way to take screenshots and I don't have a camera with me at the moment to take photos of it running on my iPhone, but it's really very nice. The page automatically scrolls down to hide the Safari toolbar on load, and the color scheme, icons, and widgets all match the iPhone UI styles much better than the standard oneSearch design. I like!