Interesting projects based on Distributed/Operating Systems
MIT has an OCW class, "Distributed Computer Systems Engineering," with a Projects Section which you might find helpful.
Check this blog entry on Mapreduce & Hadoop Algorithms in Academic Papers (5th update – Nov 2011). The problem areas in the blog entry could also be solved using non-MapReduce distributed algorithms also.
I suggest instead of going with the hype, pick a topic of your interest and work on it.