Would an artificer be able to create a staff that was meant to cast an epic spell using use magic item skill assuming the epic spell was developed beforehand?
The Epic Level Handbook on Metamagic, Items, and Epic Spells, in part, says
You can’t craft a magic item that casts an epic spell, regardless of whether the item is activated with spell completion, a spell trigger, a command word, or simple use. Only major artifacts, which are beyond the means of even epic characters to create, can possibly contain magic of this power. (73)
Thus, officially, not even an artificer with help from an epic wizard can create an item that casts an epic spell.