There are plenty of 10K drives that do not get very noisy or too hot actually. Anybody who bothers to get 10k/15k drives would be better served with an external enclosure with its own PS and fan.

PS. for anything with a PCI-X slot there are tons of SCSI 160 and 320 adapters on ebay for barely over shipping. I have a few pairs of SCA drives in the bottom mounting of 8600/9600 machines and they stay cool enough.