-> So SL/xaml is, in effect, a new .net based browser - that parses xaml instead of html and has its own display processor. This is shown clearly with SL hosted outside the browser using its own host. My point has only been that .net tech in browser senerios works today and has value, unlike what others are saying. I have only pointed out SL as a prime example.
Nope, the parsing of XAML and rendering of SL visual tree are all done in unmanaged code, core CLR is only used to expose those features to managed code, since in V1, people still needs to use Javascript which desktop developers doesn't enjoy writing and web developers are tired of writing in it too, so core CLR is just very thin wrapper around the underlying unmanaged SL runtime.
Actually, the existing WebBrowser control could be retrofitted to workaround the infamous airspace issue by rendering HTML in HWNDless mode, no need to rewrite it from scratch.
Zhou Yong