Thank you for the reference. It's nice to know that the device can power down to 1 uA if the design permits it.
Unfortunately, my arduino boards (all boards?) are based on a 16MHz clock so there's considerably increased power consumption right there. I can change out the clock crystal, but that would almost definitely break the serial communications including IDE downloads.
It also doesn't look like the sleep modes, the brownout fuse disable, and other power saving features are exposed to the programmer using the standard arduino IDE. Are they?
I appreciate the help.