+1 for multiple timelines, after working in After Effects and going back to Vegas, I miss that feature.
Besides of multiple timelines from one Vegas Pro application, you can run multiple Vegas Pros. And you can copy-paste the clips between these Vegas Pros.
Thanks Set but it's not the same thing. For example I work on a series of Car commercials periodically and having multiple timelines for 20+ spots is a great feature when needing to go back and forth for copying/pasting etc.. In fact I usually end up using Premiere for this reason.