For the TCCD project, I really would like to get a Jenkins job building things, but the problem is that everything is on GitHub and the repo is enormous due to the huge number of images. Partial checkouts with git are tricky. However, by looking at this documentation, I've figured out and tested a way to script a partial checkout using svn instead.
Say you want only the [proj]/level1/level2/level3 directory:
svn co -N https://github.com/[proj] proj cd proj svn up -N trunk svn up -N trunk/level1 svn up -N trunk/level1/level2 svn up -N trunk/level1/level2/level3
That will get you a sparse checkout down to the contents of the level3 directory.