I have an old Latitude CP of ~2000 vintage with 2 cardbus slots. wi(4) works. Unfortunately other PCMCIA network card drivers seems to have bitrotted indeed. Neither mhzc(4), nor ne(4) work. Something changed at the interface/ether level, I guess.
>From my notes, I also experienced issues with PCMCIA and CF cards in both NetBSD 9.3 and 10 i386. This was my attempt to upgrade a 1998 Toshiba laptop from NetBSD 5.1 to 10. In the end, I had to use a USB storage stick. I'll have to dig out my old laptop to get you a better dmesg, but this was at least one of the errors: wdc2:0:0: lost interupt
The same PCMCIA + CF card works fine on NetBSD 5.1.
-Joel