So my Design 1 final is a week and a half from now, and my teacher just gave us the go ahead to start building our models. We were tasked with redesigning a nearby townhouse. It's approximately 44' X 22' X 35', and our final will be at 3/8 scale. My project has these triangular enclosures that are meant to be planar and allow for new ways of entry into the model. These are sunken into the original townhouses, with parts that are protruding out from the house (think along the lines of the Military History Museum in Dresden, Germany).

We're required to use two different materials. I want my planar elements to contrast and stand out with the original house, but I'm not quite sure what materials to use. My first idea was museum board for the planar elements, and mdf for the house. I like the look of the museum board, but I'm worried about keeping it clean at such a large scale (we're being limited to white), it's ability to be crafted into sharp shapes that are ideally made of a single, folded plane, and its price. Mdf still seems like the best choice for the house, as I need to recreate the thickness of the walls and floors, but I'm just not a fan of the grainy look. 

Basswood would be a nice substitute for the museum board, but it would loose some of that contrast with the mdf, and it is still pricey. What do you think? Would anyone happen to have any suggestions for alternatives or combinations? 

Thank you :-)

Cristiano