I`ve only had a B for a couple of weeks (though I owned one many
years ago) and already considering "pairing it up" with a (used) LX
early in 2004.
Fully aware that the battery originally intended
for both the C & LX ( the Mallory PX27 & equivalents) is no more, I`m
a bit confused as there seems to be an alternative to the replacement
Power Pack that holds four 386 cells).
The Small Battery Company here in the UK sells the Silver Oxide S27PX
with the following comment:

"The S27PX is a mercury-free replacement for the once popular
Mercuric Oxide PX27 (or V27PX) battery cell that was commonly used in
several Minox and Rollei cameras. Mercury cells are now banned
because of toxicity and environmental fears.
The S27PX cells are silver oxide and produce 6.0 Volts, which is
higher than the 5.6V produced by the original mercury cell. Most
devices accommodate the small increase in voltage and function
perfectly".

User comments from group memebers consequently appreciated !