The trouble with the HAF is there is a large bulge in the door, but that is also very near the side of the case. If you mount acrylic too near the edge of the door it makes it a Fpita to fit the door. Ive looked at cutting the area you mean out myself, it could be done if you were prepaired to put the time in to do it properly. Anything less than perfect and it is going to look bad though dude.
Long and short of it is that its all or nothing with a HAF window.