From this listing you can purchase custom Throw size kits for the One House, Two House. They will be made to order. You are able to select:
the "basic" kit (just the pattern and the fabric for the top and binding), or
the "basic +" kit with one extra WOF strip for each fabric (allowance for error),
either of those kits with or without backing fabric selected to blend with the palette. A photo of the Marcia Derse extra-wide backing fabric is shown with this listing.
 
Price listed is Cdn $. Your credit card will convert it to USD if you are in the States.