If it's any easier, I have a stock 1.0 com.c modified to include this 
feature which works with no other changes to the OS.
I got a lot of requests a few weeks ago when I put a message on the list
saying that I was going to do this.  It is now done and being tested.
-Brian

On Dec 18,  9:05pm, Bakul Shah wrote:
} Subject: Re: Formal getty replacement yet?
} > I thought we wanted separate /dev/ttyXX and /dev/cuaXX devices
} > instead.
} 
} I modified com.c (+ conf.c) to do this a few months ago and
} sent out a message on one of the NetBSD mailing lists.  I
} have not reintegrated my changes back into my NetBSD-current
} sourc tree since Sep 21 but shouldn't be too hard.  They are
} yours for asking.
} 
} Bakul Shah
>-- End of excerpt from Bakul Shah