Does it have to be the bar shape? How about these, my favourite mini studio monitors
The rub is how they fit into the setup - where would I position them? Are they small enough to sit on either end of my keyboard etc? I think a bar with a woofer might be a pretty good compromise
No, they won't fit onto the corners of the PA-4X. The Bose MusicMonitor would, but they don't get very loud, just enough for enjoying music at the computer. - Although, for pure monitoring they might be enough.
But if a separate lightweight subwoofer is ok for you, I think I have a very good solution, IF this model is available in the US:
Bose Companion 50 (not '5').
I own one. The top speakers have very small stands so they fit on the PA-4X. The subwoofer only weighs 4.5 kg or 10 lbs.
Strangely, according to the US bose website, they still sell the old, heavier model 'Companion 5', whereas here in Europe the 'Companion 50' with the lightweight subwoofer is available.
https://www.bose.de/de_de/products/speak...ker-system.html