> 1. Does NetBSD support a quad 10baseT ethernet card?

Yes, under at least some circumstances.  My house gateway is an IPX
with a qec in it:

qec0 at sbus0 slot 2 offset 0x20000 level 4 (ipl 5): 128K memory
qe0 at qec0 slot 0 offset 0x0 rev 1 address 08:00:20:0d:5b:8c
qe1 at qec0 slot 1 offset 0x0 rev 1 address 08:00:20:0d:5b:8c
qe2 at qec0 slot 2 offset 0x0 rev 1 address 08:00:20:0d:5b:8c
qe3 at qec0 slot 3 offset 0x0 rev 1 address 08:00:20:0d:5b:8c

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