Its like a working horse and a _verry_ popular camera as long as it is a
'RB67 proSD'

Hi Don,
The RB67 has continued to drop in price over the past year or so.
About 6 months ago, I paid $530 for an RB67 with prism, 90mm lens, and
a 120 back.  It is in absolutely great condition.  I haven't paid
close attendtion to RB67 systems, but my skimming over prices would
indicate that your assumption is correct.  I think prices continue to
drop.

Within the past 6 months, I have bought: 220back ($110), 250mm ($160),
82mm extension tube ($80).  It took some patience to get these prices,
but I think they are fair.

On the contrary, the RB67 is a popular camera.  There are many of them
out there, and I think supply is greater than demand as the
professional market moves to other cmaera & the digital world.

Despite the weight(the RB67 is heavy, but saves me from having to work
out at the local health club), it is a nice camera.  I really enjoy
it.

Relative to the 645, I cannot compare its popularity.  The RB67 offers
a much larger negative; the benefits of such have been discussed here
frequently.

Best wishes,
TWW

Sellers must need the money very badly - mine's not for sale.