Gotcha,
Mics are two wire- DPA 4060, and the 30-40ohm figure is off the DPA spec sheet. I expect they have an aditional transistor in there to drive long cable runs. A straight batt box would probably be fine for loud material since with their relatively high sensitivity of 20 mV/Pa(34 dB re. 1 V/Pa) combined with slowly improving specs for the input stages of the small handheld recorders we use, the mics don't need a lot of additional gain, but for quiet material, they can use the added oomph.
Thanks for your explainations, which helps greatly in expanding my limited electronics knowledge- probably best sumarized as "just enough to be dangerous".
[edit]-
I'll take a look at the trafos you mention, even if it only increases my danger level.