I managed to find a photo of 3 PMX 1500 units from a Shaw headend in Canada:
Here's the link if anyone's interested:
https://www.flickr.com/photos/hpocus/4035116441/in/album-72157622517449425/If you look at it from the link, it's in an album with a few other neat headend photos- I've never even seen a PMX photo before so this is new for me (and probably a lot of others too).
On a side note, I'm sure sunlightreport from many years back would have loved to see this