To support testing multiple web sites, we should support a "changeDomain" command that will reload the entire browser window under a different domain. (This will require some JS changes.)

One big question: after we've changed domains, what will happen to the AUT? If it's running in an iframe, will that iframe be lost? What if the AUT has created pop-up windows, can we access those? Should we use sub-iframes somehow, instead of reloading the entire page?

I think testing multiple web sites at once is very unusual, so this should be low priority, but it could be really important for someone else.