It would be nice to be able to upload entire projects in a zip file to SO would it not??
Likely there would have to be some form of cap on file size and what not, but I don't think this should cause too much of a problem in terms of additional bandwidth costs, and it would come in handy for a lot of situations.
Nobody wants to deal with your entire project :) Many are happy to help with specific parts. Specific parts can be pasted in any of the many pastebin services online.
A young man asked what was wrong with his program earlier today, and posted a link to hundreds of lines of code - I politely encouraged him to be more specific with his description, and code-sample. I get the feeling this would be the general community-opinion.