I didn't respond to your original message for three reasons:
1) I'm running -current so I can't try out anything I suggest,
2) there are SO many people here who know more than I do, and 
3) I didn't know that's what you wanted to do.

Now that you've mastered pfdisk, the rest is a piece of cake.  Support
for msdos partitions is in the generic kernels...you just use mount
to get at them.  The SECRET is putting EXACTLY the right numbers in
the fstab so mount knows how to get at the partition.  The partition
starts just one track in from where you'd think, so if it's the first
partition, and there are 53 sectors per track, it starts at sector 53
not 0.  Make the partition readonly until you're sure you've got the
parameters right, and NEVER fill the disk or root directory by writing
to the msdos partition.  This may be fixed in -current, or it may not...
but it sure isn't fixed in 1.0.

The "by hand" thing that I did was fairly trivial...cat the files and
pipe into gunzip and tar.

    Greg> (3) What I'd *really* like to do - and I'm surprised there's not a method for
    Greg>     doing this - is to get the "main" installation files out of an MS-DOS
    Greg>     partition, since that's where they are already (-:  I checked tech-install
    Greg>     and found an old message from David Gluss, who kindof implied that he'd
    Greg>     been able to do it, "by hand".  I would think that as GENERICAHA contains
    Greg>     MSDOSFS support, if there was a "mount_msdos" available in the installation
    Greg>     environment that one could do it, maybe?  If David or anyone else could
    Greg>     tell me how to do this, I'd appreciate it.  I don't wanna have to try and
    Greg>     make 12 NetBSD floppies!  (-:

    Greg> Again, thanks to everyone who responded and thanks for any further
    Greg> clarification on this stuff ...

    Greg> 	- Greg