Well, as a big linux fan, I would like to do anything within linux, but Vegas is the only reason I still have a Windows XP PC running here.

Concerning emulators, wine would be the fastest way to run windows applications, but I cannot imagine that Vegas would work in wine, as Vegas is depending on lots of Windows specific things, that are probably not implemented by wine.

A solution where you should have more luck would probably be running vmware under linux, and run a real windows this way. There also scripting should work without problems, but firewire io would not work, so external monitor previewing would not be possible. Well what you could do to read you footage in would be the use of linux utilities being able to save as .avi files. But I would not recommend running Vegas this way, as vmware slows down applications like Vegas a lot, and I could imagine that rendering would take 10 times as long.

I think there are only 3 solutions, that would lead for you to a satisfying result:

1) use 2 pc's, a Windows one and a Linux one

2) use dual boot Windows/Linux

3) use a Windows pc with colinux installed (colinux is a project to run the linux kernel under windows, with almost no noticable performance impact (for more info read http://www.colinux.org)

PS: for linux mjpegtools is really worth a look, it includes a good noise reduction application yuvdenoise (which is personaly my favourite from all noise reductions filter I have seen so far as it removes most noise without any noticable artifacts) and also a good deinterlace named yuvdeinterlace, as well as some other goodies for processing video files. As these are commandline tools, they can very well be used in shellscripts. I use them for noise reduction and deinterlacing before editing in vegas.

Hope this could help you