Dry/wet mod on Boss pedals?

[Northwave]

As I'm sure you all know, practically all the classic Boss overdrive/distortion pedals use JFets for switching the effect on/off.
Has anyone attempted a mod where instead of just switching the fets on/off you could use a variable voltage and adjust dry/wet ratio?

Just a thought.
You'll notice it here, among other places:
http://freeinfosociety.com/electronics/schemview.php?id=162

[Processaurus]

Very cool idea!