Interesting, but I already use Sencha Touch to "mock up" and quickly iterate on iOS user interfaces. It's a more code-intensive approach than I'd like, because

Interesting, but I already use Sencha Touch to "mock up" and quickly iterate on iOS user interfaces. It's a more code-intensive approach than I'd like, because it's meant to produce full featured web apps, but it's easy enough to quickly produce a usable interface that I don't feel like I'm doing twice the work when it comes time to make a native app. Put several 320x480 iframes pointing to different mockups on one page and I can compare them all at once. Or I can just deploy my "mock up" as is and have the web app be instantly available on all platforms.