There are a number of teams out there looking. The Indonesians suspended any exploration for a while but it's back on now.
Blam: Thanks for sending me the thread with that ash distribution map. This could indeed explain why a hominid branch might have survived on Flores. Also since 74 kya was in the midst of a deepening ice age, the sea level around Flores would have been lower, and provided a larger land area for the inhabitants, human and animal. The land area would have gotten even larger as the ice age accelerated. [Does anyone have a link for the ocean depths around Flores?]
Naturally as the ice melted 18 kya, the land area would have shrunk rather quickly. Is this why the Flores people died out around then? Who knows how many other sub-races may have been killed off by the Toba event, or perhaps have never been found yet.