Very simple little mod. Didn't like any of the other crafting mods that affects soulgems:

This mod allows you to craft a Black soulgem at the smelter if you have arcane blacksmith and more than 80 in alchemy. Required materials for 1 black soulgem; 1 grand soulgem + 1 filled petty soulgem.

Dont know how this mod will play with other mods. doubt it will interfere with anything except a "craft soulgems" mod.