Forces deep within Gamespot have informed Kotaku that store managers have been instructed to retrofit their gameries and make it look like the 360 Core unit doesn't even exist:

Apparently an email has come down informing store managers to pull down any signage regarding the Xbox 360 core system, because once their current stock is gone there isn't going to be anymore. Seems like stores are preparing for the rumored new Core system, that comes with the 256MB memory card and wireless controllers. There are rumors upon rumors, but this one rings true.

Not exactly the true end to the Core unit that I'd like to see, but a step in the right direction. Finally including a memory card at least keeps the unit from being a total ripoff.