MIDI -> CV and state var VCF resonance control

[Synthaholic aka sPEW]

I just placed an order with PAiA for a MIDI->CV converter and I was
wondering if any of you have one of these (or another type) and what
you did with it.

I am using a FatMan and I already have a voltage controlled PWM output
device attached to it that I will connect to a CV.  I know that I can
also easily voltage control the filter cutoff with a CV and also add
some VCA tricks with CVs.  I am really interested in CVing resonance
on the FatMan VCF (state var).  I'd like to learn what methods people
have used to do this with a state variable filter.  I know of only two
myself, those being voltage controlled resistors (I have a circuit
from the LM13600 spec sheet) and optically coupled types.  I am
leaning toward the LM13600 right now, but I'd like to hear of other
ideas before I commit.  Could an OTA be inserted into the feedback
loop to do this?

Thanks.