There are tons of parallel shells out there...each seem to have their good and bad features:

http://www.stearns.org/fanout/README.html

http://sourceforge.net/projects/mussh/

https://code.google.com/p/parallel-ssh/

https://github.com/ndenev/mpssh

https://code.google.com/p/csshx/

http://taktuk.gforge.inria.fr/kanif/