My master bath had no linen closet and no where to store towels, toilet paper, toiletries, etc. I found these upper kitchen cabinets at a thrift store for $4.00 each. They sat in my garage for about 2 years, before I realized that they could solve my storage problem.
I decided to make my own linen cabinet. It wasn't going to be tall enough if I just stacked the cabinets, so I had to come up with a way to give it some height.
I built a simple box from MDF, just tall enough for toilet paper and attached both cabinets to it. I added 1/4" luann plywood to the sides to give it a more finished look, then added molding to the top (also purchased at a thrift store). It still wasn't quite tall enough, so I routed a piece of MDF and set the whole thing on top of it. I added feet, which are wooden finials ($4.00 for all 4) that I sanded about a quarter sized circle on the bottom of. I decided to leave the door off the top shelf, since it had the nice arch.