Is there and "rdist" for Mac?

[Chris Jones]

> Basically I'm after three-way master replication i.e. any box can be the 
> "master" at any arbitrary time, if that makes sense; develop on Mac, 
> test on FreeBSD, see what the Penguin busted, and any can be the 
> "master" at that time, pushing sources back to the others (but the Mac 
> will be the ultimate repository, or it might be the FreeBSD server, etc).

Sounds to me like you are describing a git hosted software project, 
which you then clone and build where ever you need it. Each clone is its 
own repostory, which you can commit to and push back to / pull from the 
central repo (which will be, for instance, the github version).