man, almost forgot about this guy completely!
ok, we're sticking with subspecies, similar to gauth<beholder.  another example would be gnoll<flind.
we still need another feat.  i adjusted the skills thusly:
Skills: Hide +2*, Listen +9, Move Silently +8, Spot +9
feeling that we need "just one more thing" to make it more than just an advanced beholder, maybe DR is the way to go.  5/--- is too much though.  maybe 5/slashing?  if not that then how about a weak tremorsense or blindsense or low-light vision?