Many thanks to Perry Metzger and Matt Thomas, actually
I only needed to change the sb0 line:
	sb0     at isa? port 0x220 irq 7 drq 1 drq2 5   # SoundBlaster
to use irq 5 instead, that made the PCMCIA ethernet work.

After some more grepping through email archives I've also
found PCIC_ISA_INTR_ALLOC_MASK though I haven't tried actually
using it yet.  It would be nice if there was an example
of this in GENERIC (possibly commented out).

  -  Arne H. J.