yeah what Superdos mentioned is acutely a Seagate Savvio Drive,  They are 04-07,  2.5"  From 36gb to 73gb. (going by what i have seen for sale),  i was told about these drives from james, from this forum. Quiet, Yes --- Smaller, Yes --- Low Power? 800ma on the 12 rail is not terrable. Heat? yes, you better have some form of cooling, not the kind of hd i would install in an enclosure with out a fan. Termination?   No.  You have to provide that… and that is where Max's (max1zzz) adaptors come in for vintage mac, making this drive an exceptional SCSI choice.

http://ixbtlabs.com/articles2/storage/savvio10k1a.html