burr coffee grinder for turkish grind

I am looking for a coffee grinder that will grind AT LEAST 1-lb. batches (up to 50 lbs.?) I would prefer roughly 10-lb. batches. The grinder must be able to produce an extremely fine powder, commonly referred to as Turkish grind. Adjustment of the grind by the user is not a requirement, so if it only produces Turkish grind that is okay. Color and appearance of machine is not important, but it must be clean and in good working order. Price range is up to $500 depending on quality, etc.