Regarding the Magic Bullet Movie Looks in V5... OK - so you can't edit the movie looks in the effect window - but you can edit the look presets in Notepad. Go to C:\Program Files\Movie Looks for Vegas\Look Presets and make a copy of the "mbl" file closest to what you want, and open it in NotePad - tweak the values, save and choose your new look in the preset drop down back in Vegas.
But they render soooo sloooowly - I bet they've slowed it down on purpose to something like 1 frame per second... I mean what can it be doing with all those processor cycles?! It's not deinterlacing or anything is it?