The datasets I run on tend to be several terabytes and all the clusters that I use utilize various distributed filesystems (eg. Lustre [1] or Dcache [2] or Xrootd [3]) to store these files across local storage on all the nodes of the cluster.
I think for big datasets some kind of support for these distributed filesystems will be necessary as most private (scientific) computing clusters use them. The complication is of course that to use these filesystems, one needs to build support for each access protocol into a python module (off the top of my head I'm not sure if they exist yet; perhaps they do). While most of these filesystems do offer standard posix 'mounting', this is usually not recommended for performance reasons.
Perhaps I'm outside of the intended use case anyway. To a certain extent this problem is solved for my field of research (of course nothing ever works all the time heh), as all LHC/OSG Computing Grid centers run the same Scientific Linux distribution with the theory being that any code that works on one should work on another.
But this sounds great for teaching classes and labs! I look forward to using it.
[1] http://wiki.lustre.org/index.php/Main_Page [2] http://www.dcache.org/ [3] http://xrootd.slac.stanford.edu/