Cobblestone generator

This is a project i've been working on for a while now (Since mid 1.8-ish). Getting the timing right for the secondary pistons has been a problem, still needs fine-tuning. you're welcome to try and figure it out if you like.
This is my creative/test/junk world so it does have other artifacts in it.
Why create this you ask? Because it's Minecraft.
Find a way to make the simple complicated, then take it one step further!

The secondary pistons (Vertical) run off of a race-track system. each repeater tick adds one "lap" to the redstone race.

UPDATE:
Unfortunately, the 1.3 release preview (intended to be identical to the full release) can cause some problems with the vertical pistons. they don't always properly fire. :/