if Yamaha made a module version of the T5 I'd buy one straight away .I'm using a psr3000 that has been made into a module so to speak !! by having all the keyboard and speakers removed, and ends cut off it reduced the size and weight and fits into a custom made flight case it includes music tech radio receiver for my midi/acoustic accordion .
So when I arrive at a gig all I have to do is plug in the mains plug and connect my speakers .....to the module !!
I've had a good look at the T5 it is awesome !!! but under the cover there are 4 or 5 I'm not sure of the Quantity module boxes and they take up the complete length of the keyboard ,so really no reduction in length is possible ,so just removing the keys ...would only be a tiny weight saving !! not worth the effort !!
I've spoken to Yamaha people a number of times on this matter and the official line is "we make Keyboards " "and the module market is not bigger enough to justify making a module !!
but I have to say I'm over the moon with my self made module
In my time I've tried most modules (not mentioning any names) setup !! so I'll stick with the PSR3000 system !! I've had my fingers burn't a few times ... the PSR3000 ticks all the boxes for me !!