> OK.  I don't understand the 'multiple MBR partitions' part

The suggested partition would require the MBR to tell DOS about at least
three partitions:

	0: 200MB of type "NetBSD"
	1: 3GB of type DOS Primary
	2: <n> of type "NetBSD"

and NetBSD wants to have only one NetBSD-type partition.  However, I don't
think NetBSD actually checks that all of the NetBSD filesystems are within
NetBSD MBR-partitions; if that's the case, then you can just point the extra 
NetBSD native partitions to the additional space after MBR-partition 1.

> (indeed,
> I just managed to get this Gateway installed NetBSD-only;

Which Gateway?  I'm leaning toward getting one myself for NetBSD.