We have NetBSD 1.6 installed and happily running on an RLX blade
server.  The blades have a Phoenix BIOS that supports serial
console redirection --- and in fact the blades have no VGA, PS/2,
or USB, and no way to add them.  It may be the case that this BIOS
does some things differently than other serial console redirecting
BIOSes.  Still, our experience may shed some light.)

> - > 	Is there any way to convince everything to share the
> - > same console port?  

Yes, at least with these machines and this BIOS.  After a lot of
trial and error, what we found to work is regular (vga) bootblocks
and a kernel that forces a serial console (i.e, with the lines
  options         CONSDEVNAME="\"com\"",CONADDR=0x3f8,CONSPEED=9600
  options         CONS_OVERRIDE
added to the kernel config).  We could not get serial bootblocks
to echo to the console, nor could we get a kernel that doesn't
force a serial console to do so.  Note: we got all this working
at 9600 bps: the blades come with the serial port preset to
38400 bps, but we had some issues at that speed.

I could go on at much greater length about things we tried that
didn't work, but we're not a lab and didn't take rigorous notes,
so I'd likely get some detail wrong that turned out to be
important.  I'll be glad to try to answer any specific questions
anyone may have, though.

---Alex