I don't know about you, but my Intellisense in Visual Studio for XAML works just fine :P
.. as long as you only want to make a stack layout and a Label 
Here's a Screencast of mine working, I'll publish a plugin soon ...
but wanted to show a sneak peek!
This is a very scalable proof of concept and has tons of possibilities!
UPDATE:
OK here's a better showing of it, there's more controls to work with ..
next, I'm gonna try to get binding Intellisense to work... I know it looks impossible.. but doesn't that sound fun?