DVDRW bay to HDD bay

My laptop (in sig) has a DVDRW drive. It is not "removable" like some laptops where you can hot-swap it for a hard drive or battery. hdparm -I tells me it is definitely SATA, so I should be able to plug a hard drive into it. Does an adapter bay into which I could put a hard drive exist?

It will work likely work fine. The two obstacles you have are first finding a hard drive cage. For some notebooks the cage that works for the standard HD will also fit into the optical bay, others need a special adapter. The second is the BIOS but it should work fine. I only have experience with Dell's. You can get cages for them on ebay and the BIOS works fine.