I highly recommend Outdoor Research Vanguard Pant as a very high quality solution for what you are looking for. The mediums should work really well for you, they are about 32-33 waist and run long. They have a removable bib so can be worn as a pant as well. You can read reviews for the pants on several sites.
Men's Vanguard Pants | Outdoor Research | Designed By Adventure | Outdoor Clothing & Gear