djst,
Interesting.
If resolution isn't the difference, what would account for one LCD being better than another in direct sunlight?
There are a number of properties of an LCD screen that affect brightness in direct sunlight: the type of LCD technology used, the quality of the material, the reflexiveness of the crystals and back material, the glossiness of the front material, etc etc. Resolution actually has nothing to do with any of this.
To give you some real-world experience: I have used the E-P1 in direct sunlight in Paris at noon, and I had no more problems framing a shot with it than I've had with any other camera I've owned, including the twice as good LCD (in terms of resolution) of the Panasonic LX3.
I wouldn't recommend attempting manual focus in direct sunlight, but I think that goes without saying. But in terms of composing a shot, confirming auto-focus, adjusting exposure and reviewing a taken photo, it works without problems.
Also, to give you some more perspective, I was personally worried about my choice of E-P1 because of the fact that it doesn't even have a hot shoe for the EVF even if I wanted to shell out $250 for it. But in the end, it turned out to be a non-issue.
To summarize, I think you may be overrating the importance of screen quality and the problems you think you'll have with the Olympus cameras. Still, if I were you, I'd go to a camera shop and ask to use it outside for a couple of minutes to try for yourself.