Great Models has that DML/Dragon LCM Diorama kit listed for $14.20.
The base is 13" long by 9" wide.
Good price for what you get. Get 2 (that will give you 2 LCMs, with 6 crew figures and 24 infantry figures from the 29th Div. for Normandy. Place them side by side. Then you just have to, if you want. expand the beach area. Get the barbed wire (see my answer to your thread in the Diorama forum) from Accurate Armour.
Also search around on Great Models. They also have "barricades" that you can put on the beach, etc...
James