I was getting the same error message like you "Still waiting for root device" when I first tried installing. I was using my old ATA hard disk, but when I tried instaling on Serial-ATA everything worked perfectly.
Since you already use Serial-ATA, try those suggestions:

• Step 1 Jumper Settings : If your system contains IDE hard disk or DVD RW then you need to play with your jumper settings. If the following settings are not working for you try vice versa. if you have Sata Hard Disk and DVD RW skip to step 2.
  
  Your rom/writer must be set as Primary Master.
  Your hard-disk must be set as Primary Slave .

• Step 2 Tweaking the BIOS : If you satisfies step 1 then time is to play with BIOS settings. Open your BIOS settings by pressing DEL or F2 key continuosly as you starts your PC. Once the BIOS screen appears try to find and change following options if they are available.
  
  ATA/IDE Mode : Native
  Configure SATA as : AHCI
  S.M.A.R.T. : Enabled

• Step 3 Download Another Distribution : This is the most effective there are many OSX86 distro in the wild but you have to choose select one for your hardware configuration. For selecting the right one search on Wiki.OSX86project.org and forum.insanelymac.com if you find anyone who posted a success message with his details then you are lucky otherwise download the various flavours and try them.

Those suggestions helped me, you can find them http://www.ihackintosh.com/2009/05/s...r-root-device/, check the comments too..

P.S. First step for you would be to enter BIOS and check if your hard disk is set as Primary Slave, and if you configured SATA as AHCI in BIOS settings. SMART is not that important i guess, but it never hurts to enable it