Reminds me a bit of Bpipe (http://bpipe.org), and Ruffus (http://code.google.com/p/ruffus/) ... though perhaps more mature? But the syntax is a bit more obtuse when you actually look at the examples (not that I mind learning it if the payoff is sufficient).

I think we'll see a lot of DSL style / scripting languages like this pop up as big data computing becomes more mainstream and people try to make parallelism easier to grok.