I can't believe I didn't know about this already.
Edited two hours later:
How, how, HOW is it possible that I have not a single ball of black worsted-weight superwash in my entire stash? My entire stash which one might, if one were to be absolutely honest, fairly describe as, ah, extensive? The ONLY black superwash in the entire house is half a 50g ball of Dale Baby Ullgarn--enough yarn for a hat for a newborn. A premature newborn.
I can pick up a ball tomorrow at the LYS by my office for Hat #1--for the rest (and there will be more) I'll have to wait for a delivery from cheap wool yarn central.