and....YES! I just picked up a 45-CT4 from an auction. It came with two leaky 45-40 NiCd packs. Today, at work (we have a battery tab spot welder), I managed to re-cell one of the packs with brandy new 2300 mAh NiMH cells.
It works wonderfully, and charges with the original charger (which is probably not what I will use long term, because, in my opinion, it's a crappy design). I'm pretty sure I can build a fast-charging drop-in charger for the 45-40 packs, using a battery charge IC, which will charge a stack of 6 NiMH cells way faster than the plug-in charger Metz sold...after all technology has progressed a bit since this design was done.
I found the appropriate (SCA-344) TTL interface cable for my F3 on eBay for $42, so I'm stoked! Working flash, repaired pack and F3 cable for under $100.