Minecraft: Fast Cobblestone Generator v2.1 (up to 110 bpm)
map download: http://www.mediafire.com/?rq2tpy2d7m3...
This is the fastest cobblestone generator achievable in vanilla minecraft.
It generates blocks way faster than you can mine them.
Still, it is just a little faster than the previous design that, in turn, is much smaller and less resource demanding. If you need one, I suggest to build that instead.
I ran a very intensive test to try to obtain the max blocks per minute output possible that, after many tries, turned out to be 110 bpm.