I now have more information on the 3COM 3C574 10/100 PCMCIA ethernet
card. Unfortunately it doesn't enable my feeble mind to make any further
progress.

Christos said that it should be supported in the latest version of Linux
pcmcia_cs. I found 3.0.0 of that package at Sunsite and checked - it
does indeed have a file that claims to support the card (and also says
"this is the only publicly available documentation on the card")

Two things from the comments at the top of the file (see
"http://www.morningstar.com/~laine/linux/3c574_cs.c") are:

  1) it uses a boomerang chipset, but without bus-master capability. I
     don't know how this will affect us because I don't know anything
     about current boomerang chipset support in NetBSD (all I know is
     that there's a #define for it).

  2) If normally gets the MAC address from the eeprom, but "future
     products may include a modem chip and put the address in the CIS".
     So I guess that means the funny stuff used to find the MAC address
     on the 3c562 isn't necessary (as a matter of fact, I tried it and
     it didn't work).

I tried setting the chipset to BOOMERANG in the epconfig call, and that
helps nothing (at least nothing visible ;-); it still gets the wrong MAC
address and panics while trying to set the media type.

So, now that I've found (kind of) a source of information, who knows
enough about the 3Com drivers to help me make it work (about the best I
can do at this point is follow specific instructions. Everything I know
about NetBSD ethernet drivers I've learned in the last couple days, and
I've made a concentrated effort to minimize even that!)

(For interested parties, I have the source tree of the entire Linux
pcmcia_cs package at

	http://www.morningstar.com/~laine/linux/pcmcia-cs-3.0.0

)