Hello everybody!
I don't know if anyone already does this but I was thinking, and then I remembered that PC Part Picker has a section for keyboards. The cool thing about this is that it automatically finds the cheapest price for you, including offer codes and mail in rebates.
However, it does have some limitations. It can't search for used keyboards on eBay, and it can only search certain stores, but there are still quite a few stores, and it's pretty cool if you're looking for a keyboard.
Link:
http://pcpartpicker.com/parts/keyboard/