Assuming that I have the following directory structure for a Python project:
config/ scripts/ src/
where should a fabric deployment script should go? I assume that it should be in scripts, obviously, but for me it seems more appropriate to store in scripts, the actual code that fires up the project.
This is really a preference thing -- however there are a couple places I like, depending on situation.
Most frequently, and particularly in cases like yours where the fabfile is tied to a piece of software, I like to put it the project directory. I view fabfiles as akin to Makefiles in this case, so this feels like a natural place. (e.g. for your example, put the fabfile in the same directory holding config/ scripts/ and src/)
In other cases, I use fab for information gathering. Specifically I run a few commands and pull files from a series of servers. Similarly I initiate various tests on remote hosts. In these cases I like to set up a special directory for the fabfile (called tests, or whatever) and pull data to the relevant subdirectory.
Finally I have a few fabfiles I keep in $HOME/lib. These do some remote tasks that I frequently deal with. One of these is for setting up new pylons projects on my dev server. I have rpaste set up as an alias to fab -f $HOME/lib/rpaste.py. This allows me to select the target action at will.