I checked B&H price for a 10x8 DD. Just under A$300 with post - ouch. The problem Pete is that we and many 10x8 users only used them for studio still-life set-ups... shoot, send off to lab, wait for confirmation it wasn't sitting at the bottom of a tank, do next set-up.. Only one DD or two needed per camera.

Caution... somebody may offer you an oldie, grooved to take glass plates instead of film.