here’s one from yong kang of singapore who found a way to plump up a skinny billy and add doors. “i had a 60cm (approx 2′) wide billy bookcase for quite sometime (they don’t sell the 60cm version anymore over here at ikea singapore). when i first caught sight of the billy nyckelby, i told myself i really have to put that on my bookcase. the problem is that the width of the doors is 40cm (approx 16″). then, an idea struck me, i could attach a benno cd tower (20 cm wide, approx 8″) next to it to make up the total width of 80cm. so i purchased the benno cd tower. new screws were attached for added stability. then another problem came, the holes in which the door bracket is to be attached to the billy bookcase is different from the benno cd tower. new holes were drilled so that i could attach the door. once these problems were solved, the doors were safely attached.