I have been browsing Apple's tech info site, and have found the 
following tool, named LocalTalk Bridge:

	http://asu.info.apple.com/swupdates.nsf/artnum/n11358

This allows a Mac with both Ethernet and Localtalk interfaces to bridge 
the above networks.

I seem to remember it being mentioned that NetBSD/mac68k does not 
support localtalk, but I wonder whether it may have something similar to 
this.

Does anyone know, or would it have to be worked on?

I'd be willing to do any testing, or any help with the development, as 
if I can get this to work I can save myself lots of money on a hardware 
localtalk bridge...

Thanks, all the best.

Matthew