There are AUI (15 pin tranceiver interface) equivilents of a 10baseT hub,
usually with some sort of upstream tap (In my office lab, I have a little
box with 4 AUI "DCE" ports and a 10baseT output.)  This eliminates the
requirement for a tranceiver per port plus big yellow coax plus 2.5m required
separation.  As far as I know, there is no AUI equivilent of the 10baseT
"crossover" cable that allows two systems to be connected with "just a
cable."

Given current ecconomics, it is probably cheaper to buy AUI 10baseT
Transceivers and the crossover cable (or hub.)  The AUI interface has
become so uncommon that equipment that specifically deals with it has
not come down in price as much as the 10baseT stuff.  (OTOH, this also
means that "data centers" all over are tearing out their old AUI-based
stuff and putting in 10baseT instead.  You may be able to find USED
AUI concentrators and cables and such for very cheap indeed (well, I
have a big box of it.)  If it's free, it might even be worth dealing
with the heavy cables and unreliable connectors :-))

BillW
cisco