from what i understood about the vastolordes is that their aren't any hollow pieces anywhere on their body period, making them 100% identical to human beings. it may be wrong though, since an arrancar is a half shinigami/hollow would be an acception based on the fact that arrancar is the army of cracked masks. i agree ulquiorra is a vastolorde, nell too could possibly be one as well. im interested to see other augmented vastolordes in later chapters. Obviously though, ichigo has a long way to go until he can finally face aizen.