It is true. LDD models are not always available to buils in real bricks but it is a reason I like the program: it allows to build virtually anything. I will consider the 7-brick idea for rebuilding. It could also make possible to build the white pressure tank under the right side I could not otherwise fit in the model.
This is a really good design. I do think though, considering the size of the wheels, this would look better as a 7 wide. The steps would also hang straight with a little bit of extra width. I would definitely like to see this in real bricks. The trouble with using LDD is that many parts just don't exist in the colours wanted. I have a feeling that the buffer plates are not available in yellow.