I get all my cobble from buildcraft quarries. Have a 50x50 one running with 50 silver chests near your base, and you have a limitless supply of cobble. Also a great mining tool if you can supply it with enough energy.yup, on the water thing Reservoir from Ender IO (it's Ingame-Description says how to use it). and Transfer node (Liquid) with n World Interaction Upgrades above a Infinite Water source.
little tip for Large Buildings using Extra Utilities: Transfer node (Items) on a cobblestone, on one side of the cobble is water, on the opposite side lava. World Interaction Upgrades in the Node for a clean, fast and lag-less Cobble Generator. (amount of WI-Upgrades = amount of Cobble)
using Ender IO's Crafter (Upgraded), Item Conduits and DSU/Drawers/Barrels you can makes a passive fast lag-less Compressed Cobble Farm
(because you said Private server i thought you had a Custom modpack xD)