i have looked at doing this as well as the euro climate control system is far more reliable, you can actually achieve the result you are seeking, and in many early models, it is a dual zone system.
to do what you are proposing will most likely be more trouble than it is worth. the euro climate control is cable driven and would require the re&re of the air distribution box. to do this, you would have to disassemble most, if not all, of the dashboard. a heck of a lot of work and the air distribution box isn't exactly cheap or easy to come by out here in north america.
'94 W124.036 249/040 leder; 8.25x17 EvoIIs
'93 W124.036 199/040 leder; 8.25x17 EvoIIs, up in flames...LITERALLY!
'93 W124.036 481/040 leder; euro delivery; 8.25x17 EvoIIs
'88 R107.048 441/409 leder; Euro lights
'87 W201.034 199/040 leder; Euro lights; EvoII brakes; 8x16 EvoIs - soon: 500E rear brakes
'70 R113.044 050/526; factory alloys; Euro lights