Well, bigger is better, and every bit as important as horse power is having the proper blade. As a production turner, I have a Laguna 16HD, 4.5 hp, and 16 inch cutting height. It runs a 1 1/4 inch blade with teeth at 3/4 inch apart. It is faster, more accurate, and safer than a chainsaw. There are a lot of lathes that are 1 hp, and you can get a riser block so they can cut 12 inches high. They work for this, but not if you are going to be doing production work. Get good blades, I prefer bimetal which are hard metal teeth. You can get carbide, but they are only necessary if you want to cut veneers. I feel that a bandsaw is much safer than the chainsaw, and a table saw. There are a couple of books out which tell you how to fine tune your bandsaw, and if you don't know much about one, buy or borrow one of these books. For cutting the circles out, I prefer a 1/2 inch blade with 3 tpi (teeth per inch). You want a wide set to the teeth, especially if you are cutting green wood.
robo hippy