I rigged this up a year or so ago. I found a pair of low powered Olympus T20 flashes, added a cheap wireless setup, and some other hardware. This is the rig I made. Future versions of it will have different spacing to fit my new M5 better, use both flashes, and mount to a tripod. Here is a shot I made with this set up. The T20 is low powered, but is enough for me to go to f22 at a reasonably low ISO on the E-PL1 and still shoot handheld.