We had a second-hand closet in our guest room but it was plain old ugly and too big for the room. We also wanted to orient the bed in another way and maybe even put in a double bed.
I used primed 18 mm MDF that I plan on leaving as is for the carcass. The doors got three coats of white paint. In order not to bankrupt myself I skipped the designer handles I saw and opted for cheaper handles from IKEA.