So, I've got the following questions:
   
   		(1) Are the com-ports really shared between the "real" ports
   		    and KB/mouse?  I know very little (so far) about the U5
   		    hardware, but certainly recall using KB/mouse/serial all
   		    at the same time on older (non-Ultra) sparc hardware.

the com ports are DEDICATED for the keyboard and mouse.
   
   		(2) Is anyone using com@ebus succesfully, esp. on a U5?

yes.
   
   		(3) Is the kern.consdev being `(null)' indicative of the fact
   		    that I'm using the PROM for console I/O?  I'm surprised 
   		    that one of the com ports isn't tagged as console in the
   		    autoconfig output.

it probably is true.
   
   	I'd have dug more into this, but was busy trying to get more of my
   	sgi's working again (hence the need for the term server and my 
   	desire to hang its' console off the U5).


the *serial* ports on the U5 are not supported.  they are the 'se
at ebus not configured' you see (the seimens chip is a dual-uart.)



.mrg.