the T43 or R61 has NEVER been considered ;)
Perhaps a stupid question, but you describe
"The Debian machine is having various configurations of Jessie
installed. Consider it a laboratory experiment. It can have
multiple installs in a day. It intentionally has *NO* internet
connectivity. It has a small partition set aside for
preseed.cfg and miscellaneous scripts."
It seems to me that it's awfully cumbersome doing "multiple
installs in a day" without a network connection. Sure, you can
burn a minimal system to a live-CD or DVD, but as soon as you
want anything more (say some of those tools for experimenting
with networking), you need to pull stuff from a repository, or it
gets VERY cumbersome.
So... how are you doing all of those installs?