How about a mirror and lots of duct tape?
The image would appear upside down, and I'm not smart enough to frame a picture that way
Maybe they'll make one of these to fit the OM-D housing?
Yeah I saw that one but:
-I don't think it can fit the OM-D housing back (due to the partial obstruction of the viewfinder), though I may be wrong.
-It still gives you a smaller viewing area, wereas I imagine it cannot rotate (unlike the angled viewfinder), it's only advantage would be the price.