So Costco currently has the new Panasonic 5-Handset Cordless Phone System on sale for $89.99. Costco list this as the KX-TG785SK model. Based off the manual and the specs online this is Costco version of the KX-TGF54B which is a brand new model - http://shop.panasonic.com/cordles...F545B.html
It is currently sold out online but my local Costco had plenty in stock. One of the cool new features is Voice Assist which will connect to your cell phone that has Siri, S-Voice and GoogleNow.
Product Link (for reference only)
Store Locator [costco.com]