Republic Tool & Mfg. Co., Carlsbad, CA, who owns the Patents for the EZ CART, was purchased by The Scotts Co. about 10 years ago. The EZ Cart will probably be branded with the Scotts name. Their primary outlets are HD & KMart, plus other National, Regional & Local Garden Center chains.
As you know, the Garden Center business is highly seasonal and typically peaks in Spring & Summer. Stocks of all garden related products at retailers will be very low now.
I would suggest contacting local Scotts dealers to determine if the EZ Cart is an item that they normally stock and if not, would they include one on their next Scotts order. They deal directly with a Scotts representative, so that would not be difficult for them.
Good luck :-)
Rb