Just kidding... I almost made it through the whole article, but my brain bluescreened somewhere around this part: 

You might imagine that we could virtualize the byref the way we virtualize the implicit property access.  In other words, we could generate a secret local and prime it with the value of the field (umm, property).  Then we could make the call with a byref to the local as the argument.  When the call returns, we could back-propagate the – perhaps updated – value of the local back into the field/property.  The machinery to do this is relatively straight-forward...

And just when I'm struggling with remoting-through-multiple-appdomains related performance issues too.

An excellent article, just make sure to fill up on CPU coolant (Dr Pepper?) before attempting it...