Well Mac OSX Lion and Sib 7 are now a reality.  When all of you who dig under the hood of these give the green light with VDL... please let us know!  :)

Key

Hi Key!

Here's some info from Native Instruments regarding Lion compatibility.
http://www.native-instruments.com/en/support/compatibility/mac-os-x-compatibility/

I know Hugh has been hard at work on updating the VDL Templates for Sibelius 7, so expect some news from him over at [url=http://www.thewritescore.com]The Write Score[/url] sometime soon.

Generally, you should be okay running Kontakt 4 [url=http://www.native-instruments.com/#/en/products/producer/kontakt-player/?page=781](or the free K4 player)[/url] within Sibelius 7 given you're in 32-bit mode. If you'd rather not fumble with technicalities in the new stages of these releases, you may want to wait a bit before taking the plunge. At least that's what I'm doing with my own rig! More updates will become available in the coming months, I'm sure.

I'm planning on installing a new HD in my MBP, so before I do that, I'll install Sibelius 7 (after it arrives in August) on my current drive and see how it fares and give everyone a heads up.  Between Lion, Sib 7 and K4, I should have an idea of how well they might play together.