I just watched the first 5 episodes of this 6 ep OVA by Gainax, and this show just floored me, it's a great watch.
Instead of describing it, i'll just send you to animenfo, http://www.animenfo.com/animetitle,1418,nilpyb,top_wo_nerae_2.html
Now, there does seem to be a Gunbuster before this...