I also cut the inner wall to get the chests in as deep as possible. It was nothing hard, just time consuming. As I was already replacing the windows, it was necessary to open up the walls and ceilings anyway. If not, making built-in furniture is a big job, if you want good results.
I live in Norway and based the design on natural Nordic design. In Northern Europe, design is all about natural materials and the minimalist look. So I added a few natural elements to the IKEA MALM chests.
I opted for all birch wood drawer fronts to replace the particleboards that come with the MALM. The birch panels are cut in an angle at the top to get a descent grip when pulling open the drawers.
I had to get a guy who had a CNC Cutter to fashion the custom birch drawer fronts. All I did was to provide him with one original MALM drawer front panel. He entered the correct measurements into his computer and the CNC cutter did the rest. It was not expensive and he billed me for a couple of hours of labour and a couple of plywood plates, totalling $500.