> Hard disk don't always contain an MBR either. I often use whole disk for
> NetBSD disks, and if that disk is going to be /home or /usr or whatever
> (i.e. I don't ever want to boot from it) I don't bother with fdisk.
> 
> Works fine.
 
Same here, if I don't need dual-boot I always put netbsd at offset 0
on the boot disk, and it has worked fine for me so far.
Note that even if you do not run fdisk, you get a valid (though somewhat
odd) mbr partition table when you run installboot:

Disk: /dev/rwd0d
NetBSD disklabel disk geometry:
cylinders: 16383 heads: 16 sectors/track: 63 (1008 sectors/cylinder)

BIOS disk geometry:
cylinders: 1023 heads: 255 sectors/track: 63 (16065 sectors/cylinder)

Partition table:
0: <UNUSED>
1: <UNUSED>
2: <UNUSED>
3: sysid 169 (NetBSD)
    start 0, size 16 (0 MB), flag 0x80
        beg: cylinder    0, head   0, sector  1
        end: cylinder    0, head   0, sector 16

On non-boot disks I have no valid mbr (at least netbsd's fdisk claims so)
and it works anyway.

-hjalmar