Adobe software, both photo and video, has a great filter called Shadow/Highlight, which enhances the detail in shadows and can bring down the highlights.
For people that are familiar with this filter, is there a similar 3rd party filter for Vegas 8?
The Adobe highlights/shadows tool works by creating a mask around highlights and then processing the masked and unmasked regions separately using levels. Formerly (before I got CS3) I always did that process manually (draw a soft mask around the highlight, select/copy/paste to create a highlight layer, adjust layers with levels/curves, flatten image). In fact the manual process can still give superior results.
So that is the process you have to duplicate in Vegas, but motion does make it more tedious.
Have you tired Magic Bullet Looks? The $99 upgrade from Red Giant will work on your Vegas 8 Pro installation without you having to buy the full $400 retail version. I'ts quite the tool for post-production color correction... It truly is a Magic Bullet.
velvet matter looks like it has the closest thing to this, short of doing compositing in Vegas to emulate the effect (which would take up a few tracks).
*I haven't used the VM product, but judging from the demo it looks like it does something like this with fill light.