I really like that layout and I think it would be perfect for a wireless gamepad I want to make. I want to keep the layout but design a new circuit which would work with a nRF24LE1 module instead of a Teensy. If the routing doesn't turn into a nightmare, I also want to try to add a USB connector which would power backlighting LED's. So, the keyboard would work in wireless mode all the time, but you could plug it into USB to turn on the Las Vegas mode
That way you have long battery life, but backlighting too.
These modules are quite cheap (7$ shipped) but need dedicated programmers. The programmer is easy to make and the parts cost about 10$.
And of course I would need a battery to power the module, but I think a Lithium cell battery should be able to give a few weeks to a few months of charge.
The USB dongle would be a nRF24LU1+ which go for about 10-20$ on ebay depending on model and can be programmed with the same programmer as the keyboard controller module. And the firmware for that is already ready and waiting.
Do you have KiCad or Eagle files of your V1 PCB? Can you please send them over to me, so I don't have to start from scratch. Thanks!