I would not try to do the entire wedding in one edit, but instead break it up into ‘church’, ‘reception’, ‘interviews’, ‘highlights’ etc and have separate veg files. If you have changes, you then need only render out the changed project.
It does make calculations more tricky when you start using VBR rendering for long projects, but a simple spreadsheet can assist in tracking durations.
I use Vasst Ultimate S Pro 4.x for multi-cam editing. It is much more flexible that the multi-cam tool that ships with SVP.
My system specs: Intel i7 970, 12GB RAM, ASUS P6T, Vegas Pro 10e (x32/x64), Windows 7 x64 Ultimate, Vegas Production Assistant 1.0, VASST Ultimate S Pro 4.1, Neat Video Pro 2.6