Here's a link to a system I built a while back:
http://cocoontech.com/forums/topic/24657-16-hard-drives-1-case/?p=195985
Any hot swap server chassis will be loud, so I'd get one that uses large fans and swap them out for quieter ones. The Norco RPC-4216 case I used takes three 120 mm fans behind the bays after you buy a $10 bracket. I chose that particular case as I also wanted two Blu-ray drives for an all-in-one box. I also sealed all the holes on the case and used electrical duct putty so 100% of the air flow would go past the hard drives.
http://cocoontech.com/forums/topic/24657-16-hard-drives-1-case/?p=195985
Any hot swap server chassis will be loud, so I'd get one that uses large fans and swap them out for quieter ones. The Norco RPC-4216 case I used takes three 120 mm fans behind the bays after you buy a $10 bracket. I chose that particular case as I also wanted two Blu-ray drives for an all-in-one box. I also sealed all the holes on the case and used electrical duct putty so 100% of the air flow would go past the hard drives.