After BBextras.com went dark a few weeks ago I know many users have been looking for a replacement OSX theme. While it is not exactly the same as Peters BBextras OSX theme the OSX theme from Hyda-Hq.com is actually quite slick and reasonably priced at $6.
The theme is available for the 8100, 8300, & 8800 series devices in all 3 Icon, Zen, & Today formats. The only downside is that from what I understand you have to purchase each separately.
The author, Corey, has done a great job of detailing exactly what is offered in the theme since there is no trial version.
This theme only includes these iPhone style icons: Browser, Email, SMS, Phone, BB Messenger, Maps, Calendar, Contacts, Notes, Camera, Alarm, Tasks, Calculator, Media, Brick Breaker, Manage Wireless Connections, Blue Tooth, and Options. The other icons are default. Also, the sound profile icons are invisible. I did this on purpose so I could keep the banner clutter free. I find it best to set a Convenience button for profiles in options.
If you are interested you can pick up a copy at http://hyda-hq.com/