Possibly a bit OTT but these guys seem to have what
you want:
http://www.bb-elec.com/product_family.asp?familyid=145
At least 2 prolems :
1 : The price. It's looks like it'd cost me about $600 for a couple of
units. For that sort of mony, I'll run 'permanent' RS232 cables to all
the rooms where I hace classic computers...
2 : It appears I need an ethernet port to configure them. I really don't
fancy trying to write suitable configurtation software for one of my
PDP11s or PERQs...
-tony