In case no one has figured it out yet, the GTX was available only as a hardtop or ragtop, so there cannot be a 4-door GTX, Hemi or not.
Around 1986, there was an article in the first High Performance Mopar issue on two Hemi 4-door Coronets. One of them appeared at the B-J auction a few years ago. The other was white, I believe, and I think both of them were ordered and sold new around Kansas City.
In addition to the Brazilian GTX (I think it was based on the Aero-Willys?), Argentina had a more proper GTX, which you can find
HERE!