Keyboard circuit (was Stretch tuning a resistor string)

[Haible Juergen]

	>A temperature stable constant current source can be made with an op
amp and
	>3 resistors, such a circuit was used in  the Moog 952 keyboard.  

I wonder, has anybody built a synth that had a temperature *tracking*
current source
to compensate for the expo converter error ? There was a Curtis chip that
had a 
temperature sensor on chip to track the reference voltage of a DAC. Should
be possible
to do the same thing for the reference of a keyboard resistor string,
footage switch voltages
and so on. Not for external CV, of course, which severly limits the
usefulness.
But just out of curiousity - has anybody done this ?

JH.