If you don't want to DIY, you can get complete Powercompact fluorescent hoods from Coralife.
Here is their 20" 28W Aqualight
http://www.esuweb.com/new_site/ccc_53000
Here is their 20" 96W Aqualight
http://www.esuweb.com/new_site/ccc_53101
I got my 36" hood from King Ed. You could probably check with J&L or Aquafanatics to see if they could bring one in for you as well.