250swb,
Lots of good comments there.
On monopods: never mind the hype about mirrorless cameras as "DSLR killers": for me, good modern IS like that of the E-M5 is a complete monopod killer. Did anyone ever get four stops of lower shutter speed benefit from a monopod? (Even my tripod is rather lonely.)
On lenses, one other possibility that is intermediate in lens brightness and cost is using adaptor mounted 4/3 SLR lens like the 12-60/2.8-4 or 14-54/2.8-3.5. But only if you can get around the not-so-great AF speed by using techniques like prefocusing where the subject is going to be.
I have both the 12-50mm kit zoom and the Panasonic 12-35mm f/2.8 zoom, both are weathersealed. ...
I wouldn't go down the route of a monopod/tripod with the OMD in an active environment ...
