There are many different ecover design services out there. One of the newer ones is Dynamite Covers. While equal in price to some of the higher end designers, the quality is top-notch, especially the photo-realistic reflections and shadows. The graphics contain lots of little details which help make the product or service they represent seem more tangible and real. Here are a few examples of their work:

If you can afford to hire a designer, Dynamite Covers might be just who you are looking for. You can see a larger gallery of samples on their site. Click here for more information. The parent company, Implix, also offers a great two-tier affiliate program. More info can be found here.