No, I have a late 2009 MBP, but no adapter to test it with.
I did see the comment on the Apple Store that was referenced, but find that just a little hard to believe. As I said, I have the exact same monitor, running at it's full native resolution, using a single DVI cable (and another monitor running 1920x1200). It's on a Dell system running Windows 7, but if Windows can do it, odds are so can Mac OS X.
Of course you could always just call someone at Apple to see if they have some specs internally that may not settle this once and for all. Everything I can find says you should be fine.
* I have the same monitor running it's full native resolution via a single DVI cable
* According to Wikipedia (and since it's something that can be copied and pasted from somewhere else, it's probably pretty reliable) the DisplayPort spec should provide for ample bandwidth
* Also according to Wikipedia, around late 2008, the DisplayPort standards group mandated that all devices be at compliant with a minimum of the 1.1a spec
* Mini-DisplayPort ports should be every bit as capable as their normal sized counterparts
If I had a MDP adapter, I'd be willing to test it with my monitor, but alas I don't. Still, I would be quite surprised if it did have a max resolution of 1920x1200, because there's only one DVI port on this monitor, which would make it quite the trick to use a dual link adapter. My guess is that the person who made that comment on the Apple Store meant well, but didn't know what they were talking about.