The firebeetle claims 10uA and from memory is pretty close on a tinycurrent, or the Unexpected Maker boards [0].
You might be able to fix your existing boards if you look at the schematic and remove any unnecessary draws (voltage measurement dividers and always on LEDs are a good place to start). To get into the <20uA range the board needs to have an LDO with a low quiescent draw though, and designed so you can shut down power to the eink driver.