The result is very cool indeed. Click here to see it in action (um, using an iPad, naturally; if you have an iPhone, it will still work, but the screen is a bit small to do anything meaningful).
Alternatively, you can watch it here:
This code should (fingers crossed) make it into the next release. It's still "alpha" at the moment, but several people have asked for JBrowse on the iPad, and we do hate to disappoint.