Bought a great enclosure from @psychotiller, but ran into a few problems.
The depth of the enclosure is about 33mm. My Gen ACE batteries are about 50mm tall. The positive and negative prongs stick up vertical from the battery. Bending it is a no-go, as I would just damage the wires (the ends of the leads are very ridged).
Dave recommended taking apart the batteries and removing the hard case. While I’m reluctant to do this, this may be the only way. Any other suggestions from the net?