Does windows phone 8 fully support touch events within the default browser?
Does it work out of the box so that arbitrary touchmove events can be detected by a web-p
It looks like this will be similar to IE 10 for Windows, with some exceptions...
From MSDN, "Web development for Windows Phone":
Unsupported features in Internet Explorer for Windows Phone OS 8.0: The following features are supported in the desktop version of Internet Explorer 10, but are not supported in Internet Explorer for Windows Phone OS 8.0.
...
CSS Touch views – specifically overview, scroll, and accelerated scrolling.
Rotation and angular events as related to gesture events.
UPDATE: The link in your update works in the IE 10 for the phone. Touch in the SVG canvas draws with multi-touch. (It doesn't scroll the page in this area but does on the rest of the page).