Use siba's blb importer for Blender 2.6+Id post a link but i dont have it on hand. with enough searching you can find ithe posted it under his original account or under his Conservative account
I got the thing but I cannot seem to find a 1x4 .blb file.
i don't know why you are bothering to import the blb, itd probably be easier and faster just to make a cube of the same shape and map some textures to it
But then its gonna be loving huge ingame