Just to give this a kick along (it's a very interesting thread) - has anyone seen or tried Voightlander 222? It looks similar but even more dilute than Dan's offering.
I have been tempted to try it with microfilm, as at pictorial exposure these films are really 'under-exposed'! Also, as a 'frugal' photographer, anything that is 99.1% water, HAS to be good! (if it works, of course!).
VOIGHTLANDER 222 (From Phot-O-Vergne Wiki)
Na SO3 (sec) 1 gm
Na CO3 (sec) 6 gm
Glycin 2 gm
Water to 1 litre
Times vary from 12-15 mins for over-exposed negative to 60-120 mins for under-exposed negatives. http://www.photocrack.com/photovergn...IGHTLANDER_222

From danqu TP-78, a film developer formulated for Tech Pan and similar high contrast slow speed films.
In this order;
NaSO3 1.5 grams,
glycin 3 grams
NaCO3 3 grams
A less sulfited, less carbonated version of D-78.