Currently implemented as actual material switches are $selfIllum as $selfIllum and WorldVertexTransition as WorldVertexTransition.
$alphatest changes blend mode to BLEND_Masked, $translucent changes to BLEND_Translucent and $decal uses a separate Deferred Decal material.
If more people are interested and need more than just the masked change, I could add code that makes it look for switches with the same name as some vmt parameters?
Feedback requested.