Ultra low power voltage translation

I'm looking on the best way to interface 2.2V and 1.8V systems. Direct connection draws ~40uA. I only have 20uA in my budget. I have tried a bus switch solution, but apparently they are optimized more for speed than for power, and all of them contain pullup resistors of 40K or less drawing too much excess current. I need two logic lines down, two logic lines up, and one logic line bi-directional. The speed is not critical to the design. Thanks for any thoughts on this.