I'm running WKO on a mac using crossover, which is a commercial front end for wine. This allows you to run WKO without having to purchase windows, and virtualization software. Crossover is 40 bucks.
A couple of caveats-- WKO loads fine with Crossover's installer, but the numbers on the charts won't display correctly without a simple hack. You have to use a native microsoft mscvrt.dll file-- which has to be copied the the cyclingpeaks directory. You also have to configure wine to run that file as native.
Caveat #2 -- wine currently has a very hard time handling serial-to-usb. There is supposedly a workaround, but it doesn't seem that too many people have gotten it to work for linux or mac (for any serial-to-usb application, not necessarily a power meter). For those who use Powertap or Garmin, there is an easy way around this issue-- just download to Garmin Training Center or to PowerAgent and export the files in the appropriately supported formats and import them into cyclingpeaks.
This brings me to a final observation-- it wouldn't be hard for cyclingpeaks to work with codeweavers to get WKO fully supported under Crossover. The .dll problem is easily remedied. Of course, the biggest issue has to do with fixing the download situation. This, though, should not require the level of resources required by fully porting WKO into native Mac code. As to market share, well it is not really forthright to suggest that Apple controls only @8% of the pc market, because the vast, vast, vast majority of wintel machines in that analysis are used in the enterprise setting. Apple sales in the home pc market, and especially with students using laptops are a fair amount higher. Those students who are switching to Macs, along with many others who've had positive experiences with iPods and iPhones are future customers.
Since switching to Mac, what has surprised me most are the number and quality of applications available at very reasonable prices (~$50). So, while I don't doubt when Andy says the company doesn't see profitability in offering the product to Mac users, I'm still a bit perplexed by it, particularly when an option like Wine would require NO rewriting of code.