I guess people aren't really collecting Apollo
workstation stuff.
DN3xxx et. al. are just coming out of the bottom of the bathtub curve.
Same with VME Sun 3 and 4.
Most of the mid-80's workstations have been recycled now.
There is also the little problem of software for them, if you don't want
to run NetBSD.
To be honest, the first lot with the disk controller and network card
were of more use than the memory and video card.
Keeping Apollo gear going is going to be tricky. At least the Sun 3 hardware
docs have mostly leaked out. I've heard of very little detailed Apollo HW
info out there. A couple of years ago, I was trying to get the guy who was
working adding more driver support to BSD to get the info he had reverse
engineered, but didn't get anywhere.
I've been in contact with the person responsible for Apollo product support
at HP about what hardware info they got for the machines, and it doesn't sound
like much made it out there from the east coast.
Similar things happened when HP took over the 68k-based 1500 product line from
TI.