I did a short industrial training bout 4 years back at a biotech consulting firm, one of their clients were growing organs. Very interesting really. Their pioneer product at the time were urinary bladders, simple enough structures to grow. They basically get a biopsy of the clients tissue sample, culture the cells and grow the organ on a scaffold immersed with nutrients and growth stims. Since its the clients own tissue, its practically an isograft - no host rejection of the organ. Nifty as f***.

Simple cell lines are easy to culture, but organs are a mess of many different cells to begin with...its gonna be some time before they even come anywhere close to cloning something as complex as the kidney