Actually, the best-suited hardware of all may be the DECstation 5000
series (except 200) and the Alpha 3000 series with the ioctl asic.
The ioasic has a DMA engine that can pump out an entire packet (up to
4kbytes, aligned to end-of-page) with only one interrupt.  Same deal
with reception, tho' the driver may have to poll to find end-of-packet.

The intersection of people who have the dec hardware, Mac hardware,
and interest in localtalk maybe empty, tho'.