Let the hive mind of Engadget get that for you.
"We need a digital camera that can be switched on and fire off that first shot fast. It's not a commonly tracked statistic on any review site, and nobody seems to have this information for every camera. We were hoping other readers could inform us as to what small digital cameras can fire off their first pics in under a second (ideally under half a second). It needs to be small, but mostly, just really quick in operation. Thanks!"
Well, just got a 1Tb one of those from a buddy who went to South Korea last week...
It actually uses a Hitachi HDT21010SLA360 drive. Still couldn't find much info on it since it seems to be a asian product but so far from my first 10-15min with it, it's quite good. Very silent, low heat and the transfer rate seems to be reasonable at least: got 30mb/s without any problems so far.
Unfortunatelly this is a 16mb cache drive only BUT at least, 7200rpm.