When you get this built you will be the envy of the region! Your Ryobi motor is approximately 13 hp. so it should be enough to cut through most lumber. cutting lumber with it will definitely be a possibility. Wood gears has a shop built band saw and, although it's not to the scale you are talking about, it might give you some ideas on the build.
at about 5:02 he shows how you can cut your own pulleys. If you make them you can make multiple sizes to see which works best for different applications. Hope something here helps!