Good ideas all, but I can't use them.  :(

Supercaps cost too much and there's nowhere to put them.

The basic problem is that the customer WANTS a coin cell, because it
fits the space they have available, but I'm not aware of any coin cell
that has a low enough impedance for our moderate pulsed energy needs.
(<50mA for a few 10s of mS)

I'm not sure if being able to buy the cells at the corner store is an
unstated requirement or not.
--=20
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