What about the GF series?
I'm a big fan of the GF1, but from a technical standpoint you are sort of in the same boat as the E-PM1. I'm not sure how some of the more recent GF sensors compare, but none seem to get rave reviews.
As for the LX7 vs RX100, a case can certainly be made for going with the less expensive option. But then you can also look at a bunch of other high end P&S options.
My choice for a pocketable camera <$500 is the RX100.
If my budget was <$300 and size didn't matter so much I'd go with Fuji X10.
And if I wanted to be below $300 and pocketable I'd probably go with a Canon S110 or a Fuji XF1.