It'd be pretty cool if they sold a 61key "upgrade chassis" where you got a 61key version with no guts and no end bells. Then you could just - using a screw and nut driver - transfer all your boards over to the new chassis. I bet there are ones who would buy it. It might look a bit weird to have the controls centered in empty space, but it would look any more weird than a Virus TI full size keyboard that's left justified.
I like the concept. My view of this sort of upgrade route is that it would involve extending the right hand end. I haven't had chance to investigate the way the chassis end plate is fixed to the base, but if it's bolted on then it could be simply removed along with the wooden end cheek. A new base extension section complete with hinged top bolted on and the old case end and wooden end cheek fitted the end of the extension. There would also need to be a replacement piece of wood for the extended front. None of this is that tough.
The new keybed would probably have different fixing holes, so they'd need drilling (to a template) . If the existing scanner can't handle or be upgraded, then the new scanner ( probably a Arduino based micro controller or similar) can be mounted in the extended section. I think the exsisting midi sockets are PCB mounted, so integrating a separate scanner via midi will need some lateral thought. But power for the board should be fairly straightforward.
I'm hoping that the p6 scanner will simply be happy scanning the extra 12 notes.. We'll see!
With this approach the existing control panel would appear to be moved over to the left. But that's probably good and no different to the sort of arrangement found on several Nord synths.
I know it's probably going to sound like sacrilege, but I've also been thinking that if I end up adding a scanner micro, what else could it do? I think the extra panel space could be used for an alphanumeric display, like a backlit 16 char lcd, an alpha dial and enter button. This could provide access to the p6 program name text that you only currently see if you're using the SoundTower editor. It would also allow quick scrolling through presets (beyond the current bank). Something that is cumbersome at the moment and involves two hands. Both these extras would make it much easier to access your programs and also identify them! All to often I'm thinking now what did program xxx do and where have I used it... Do I need to keep it, is it referenced by Setlistmaker??? Etc etc
Yes I know that this isn't necessarily in the spirit of why the p6 was created and I'm sure they'll be plenty of retro-heads tutting, but it makes something that is sonically brilliant much more functionally useful. Especially on stage in a multi keyboard rig.