[sdiy] AfterTouch - adding to Fatar synth Keybed ?

[sleepy_dog at gmx.de]

Hey all,

say I have a Fatar synth action keybed lying around. When I bought it, 
Doepfer wasn't offering the Aftertouch option anymore.

Is it effortful / expensive to add such a feature in other ways than 
using the original aftertouch band (I assume its such a foamy thing?) 
from Fatar?
They won't sell to end customers, I already asked... (a couple years ago 
anyway)

I had some insane ideas of adding a few cheap MCUs to the thing, and 
then a DIY hacked capacitive sensor (say, adhesive copper tape, one 
piece for the key, one for the base under the key) under each single 
key, manually... but I have no idea whether one can actually access the 
necessary places properly and attach those, without breaking anything.
(That would give polyphonic aftertouch, though, which sounds neat, 
although I have no idea how useful that actually is, or more an 
annoyance ;) )
Since the types of MCUs I use may have something like 32 mux'ed ADC 
channels and the needed rate of change for those finger modulations may 
not be super fast, I guess this could work, but it sounds like a bit of 
a PITA .

Other ideas?

Regards,
Steve