Molex to SATA power adapter from a Cooler Master modular PSU?
IT WORKED! This is what I did:



For those trying to do the same: Observe that the sketch I made are female connectors. This means when you go to do your male molex connector, you should flip it around. Pay close attention to that, otherwise you'll be sending 12v into your 5v rail and probably fry your harddrive.



Applied some shrink tube (also on the leftover wire that is 3.3v). Turned on the system after testing with an old spare 2.5" 120GB HDD and voilá, they all showed up after that:

  *-disk
       description: ATA Disk
       product: KINGSTON SV300S3
       physical id: 0.0.0
       bus info: scsi@0:0.0.0
       logical name: /dev/sda
       version: BBF0
       serial: 50026B725307A44E
       size: 55GiB (60GB)
       capabilities: partitioned partitioned:dos
       configuration: ansiversion=5 logicalsectorsize=512 sectorsize=512 signature=118c8db8
  *-disk
       description: ATA Disk
       product: WDC WD10EARS-00Y
       vendor: Western Digital
       physical id: 0.0.0
       bus info: scsi@1:0.0.0
       logical name: /dev/sdb
       version: 0A80
       serial: WD-WCAV5P072200
       size: 931GiB (1TB)
       capabilities: partitioned partitioned:dos
       configuration: ansiversion=5 logicalsectorsize=512 sectorsize=512 signature=000eb003
  *-disk
       description: ATA Disk
       product: WDC WD15EARS-00Z
       vendor: Western Digital
       physical id: 0.0.0
       bus info: scsi@2:0.0.0
       logical name: /dev/sdc
       version: 0A80
       serial: WD-WMAVU1508779
       size: 1397GiB (1500GB)
       capabilities: partitioned partitioned:dos
       configuration: ansiversion=5 logicalsectorsize=512 sectorsize=512 signature=cebcfd2a
  *-disk
       description: ATA Disk
       product: WDC WD10EARS-00Y
       vendor: Western Digital
       physical id: 0.0.0
       bus info: scsi@3:0.0.0
       logical name: /dev/sdd
       version: 0A80
       serial: WD-WCAV5P241367
       size: 931GiB (1TB)
       capabilities: partitioned partitioned:dos
       configuration: ansiversion=5 logicalsectorsize=512 sectorsize=512 signature=00094ed0
  *-disk
       description: ATA Disk
       product: TOSHIBA MQ01ABF0
       vendor: Toshiba
       physical id: 0.0.0
       bus info: scsi@4:0.0.0
       logical name: /dev/sde
       version: 3M
       serial: 84EFC3DXT
       size: 465GiB (500GB)
       capabilities: partitioned partitioned:dos
       configuration: ansiversion=5 logicalsectorsize=512 sectorsize=512 signature=77e39da9