Don't be afraid of 1.8 :D
This plugin allows you to change result of cobblestone generator depending on which block was in the space before.
It was created as a reaction to fixing the obsidian-generator bug.
Features
Restore obsidian generator in minecraft v 1.8 (if it will be released as CraftBukkit)
Create your own custom generator combinations (carpet -> smooth stone, mushroom -> sponge, rose -> redstone block, torch -> glass, ...)
Support for water-less rules.
Support for world- or area-restricted rules.
Both ingame (commands) and file (config.yml) configuration