the power door locks should not be a big problem for the coupe .
buy a good brand name central locking kit and just use 2 of the door motors.
hardest part will be drilling the doors and door pillars to run the wires into the cabin .
i use Mongoose or Vision brand and have no problems , Auto watch or Dynamco/Cyclops should be ok as well. i would be very wary of any of the elcheapo kits that you can get that dont have a name on the box. i have seen way toooo many of these stuff up causing doors not to be able to be locked/ unlocked or even opened.
you can get after market electric window setups but i recon that they are a sad compromise. if you have had factory electric windows before , i doubt that you would be happy with the after market jobs.
you could try
Electric-life in Victoria Aust PH 03 93833511
they specialise in supplying replacement factory type electric window gear.
dont know if they go back as far as the coupes though ??????