Although anything's possible with enough determination, it'd be very costly and especially time consuming even for someone who knows that car inside and out. If you're really that determined, you'ld probably be best to find a car at a salvage yard with ECC because you'll need to remove the dash, dash harness wiring, ALL controls and sensors for the ECC system. I wouldn't consider it either w/o the OEM climate control manual and wiring manual as well plus it's still possible that you might run into misc electrical problems that I'm not thinking about here at the moment.

It'd be VERY costly to buy all those parts new so used would be best but it won't be exactly easy and is likely to be problematic debugging it, even if connected correctly.

If you really think about it, manual climate controls really aren't all that bad, especially being that that system is almost troublefree in comparison. Non of my cars have ECC or ACC and I'm glad as I wouldn't want the problems I see with those cars using ECC. Simpler is often better.