I'm a digital sci-fi/fantasy/horror illustrator. I've been in this genre as an artist since my first magazine cover for Analog Sept 1998. I started working in digital as soon as Win98 came out.
Since working in digital, I've developed a method that allows me to bypass the 'sketch stage - which I feel forces my clients to have to 'imagine' what the final will look like, and instead present a full color illustration as your first sketch, anticipating that changes will be requested, anywhere from major overhauls to simple fine tuning. So while my workflow may seem unorthodox when I send you full color illustrations as a first sketch, rest assured that it doesn't necessarily mean it's done (unless it's exactly what you wanted of course).
I normally transfer all rights to my clients if the idea isn't mine, and my finals are poster size at a quality printable 300 pixels per inch, just in case you need to make promotional posters.
Frequent feedback during the creative process is always welcome.