You want this, I want this. We all want this so damn hard.
The latest development build of Chrome includes a fully functional mobile device emulator, complete with user agent spoofing ant touch simulation. I blogged about it here just a few minutes ago.
Want to check it out risk free? Check out Google's "Canary" browser in the Chromium release channel.
This update is absolutely transformative if you're a front end engineer or visual designer.