In XHTML 2 any element may have a src attribute
What i get from this, is that every single tag may have a src, instead of a body within the document, or, in other words:
<div src="mysite.com/badstuff" />
this one has a simple sollution tho, i think it should be fine to restrict the src attribute to only IMG, and not allow it on anything else.
In XHTML 2 any element can now also be the source of a hyperlink, since href and its associated attributes may now appear on any element.
and then, we open up a whole new relm when we start talking about XHTML Events...
I'm sure there are probably other things within the XHTML 2.0 specs that are going to have to be looked over, but at least this is a start.