I don't think I've ever seen a mid-mount like that, Ted. Usually it's the Berg (or copy thereof) or the Mendeola/Coolrydes/Joel Mohr (I don't know who made it first) style with the red polyurethane pads that bump up against (instead of bolt to) the frame horns. Could be home made? Al
PS- Too bad you had to spring for more new trans guts. I undestand that's fairly common, though; so many transaxles have been rebuilt numerous times and are just plain worn out. Up here where cars have more of a shelf life (winter/salt/rust/death) it's not unusual to find a trans that someone took out of a rusty car and put it away. The trans that my friends gave me so I could pirate the case (and side cover) for the 5 speed was out of a 1978 convertible, had never been apart, and the gear stack (and ring & pinion) look so good that it doesn't need to be rebuilt.