I'll throw you in software forum for good measure.
For what's it's worth, I don't really shop around for Mac compatability, however I do know (due to articles in various magazines) that there are a few companies that provide pre-loaded software. I know Kingston does, as well as Lexar. There was one other rather funny name that I wasn't too familiar with...."King Kong" perhaps? I don't know that "King Kong" is 100% accurate. Anyway, like I said...most "reliable" software is going to come preloaded....which , of course banks on the fact that you purchase the product.
What type of thumbdrive do you own? I do know that people develop open source software packages between Linux and Windows compatability where it doesn't exsist within the drive....just not so sure about MacOS.
I hope I helped even a little bit....I'll stop rambling now :P