If Catdog doesn't have any prototype boards left, you may want to wait until I build some 'pretty' NICAM decoder boards.
It will likely take a couple of months by the time I lay out the PCB, and then slip some PCBs in with a work job for fabrication, then assemble the boards.
Not sure of costs, have yet to look into component sourcing - NZ$ is high vs US$ which should help.