[chris wood] "i'd like to store the projects close to their original high quality for future use (re-editing?)"
Since your original media is AVCHD (a heavily compressed format), ANYTHING you do to it (short of uncompressed formats, but that would be substantially larger than your original media) will compromise the quality.
This may sound like a "Duh" response, but why not just save the original files? You just need the original media files and the last .veg file and you can resume your editing from the last time you opened the project. (I just recently did that with a really old .veg file from Vegas 3.0). Do a "Save As" with the "Save Media" box checked.
Steve Mann
MannMade Digital Video
http://www.mmdv.com