In fact, my pic shows the Pa 4x top projected on the Korg M3 module, so This is the shape of module already formerly produced by Korg.
Would be perfect addition to any Synth workstation.. Like Kronos or the new and upcomming Yamaha Montage (still to be anounced) or a stage piano like Nord stage or Roland RD800...
I once had a setup consisting out of a Yamaha S90Es, vsynth GT and the Audya 4..which convinced me that having an arranger module, works almost as good as having a real arranger keyboard. and with not having any 88 key TOTL arrangers available a module would be a great thing.
Still wondering why the formfactor of the M3 was left behind.. i briefly played an M3-88, and loved how you could remove the module from the keybed and place the module behind your arranger that reisded on top of the 88 keybed of the arranger..
actually the M3 is one of the things i am currently considering to add to my T5, i really prefer having 2 manuals 88 piano keys and 76 synth keys directly on top of eachother like an organ.. having the T5 on top of the Kronos created the usuall height gap which does not work that well when playing the arranger from the 88 keys, grabbing over to the controll knobs of T5 is just to big a move..
I never understood why they moved away from this modular setup with the Kronos..