I think you might have been confusing the Receiver with the HSX.

No, he isn't confused. Frank did indeed get a version of displayserver working on the receiver. The thread where he reports his success (and I think has some instructions for doing it) is here.

Tony Fabris managed to get DisplayServer running on an early version of the HSX kernel.

Negative. I did not even ever attempt to do so. I stated that it would be feasibly possible to port displayserver to the HSX, but never tried it myself.