This just in from the developers of Aion, a Korean MMO that it currently in beta.

We have plans to implement an inverted mouse option. This was part of our early alpha testing feedback that we gathered. This along with a handful of other options should improve usability for the west.

Also, just a note to the folks at Voodoo who broke this story. It's not a "reversed" mouse option or even an "inverted" mouse. It's the One True Mouse.