I ordered my TF700-DOCK-CG from AAFES at the end of October. They infomed me last week that the keyboard was on backorder and that they were dealing directly with ASUS to resolve the issues and get their orders. Today I received my keyboard sent directly from ASUS and it is a TF500-DOCK-CG. So for me this confirms that the TF500 is going to be the replacement for the TF700 Dock. Not sure what the exact differences are from the TF700 Dock.
I can only assume that the reason they went to a single format dock for the TF700/TF201/ and upcoming TF500 was to standardize to eliminate confusion and to save money.