Well I've made a slight bit of progress in the past 4 months.
Took me ages, but I managed to hunt down an MR2 4AGZE alternator and bracket.
The significance of this is that its the best way to mount an alternator on the exhaust side. The bracket is solely for the alternator and nothing else.
The alternator itself has special heat shields also and runs an external regulator (to keep it away from the heat).
Alternator test fitted up:
Something else significant occurred, the key to it is in this photo: