Lift wardrobe

Hi, I have a issue with my new loft extension. The space for the wardrobe is partially under the eaves and it needs to follow the contours of the eaves and the ceiling also allowing space for a velux window to open. Hence the shape would be a bit unusual. Square with a corner cut off. I don't need drawers and shelves just one full width shelf at the top snd a hanging rail below. I'm wondering how difficult it is to make and what the best materials would be given the floor is oak veneer. Thanks for any thoughts.