Instead of hiring heavy equipment and beginning the expensive process of rock removal, which in my experience is rarely completely successful, we opted for raised beds. There are several benefits to raised beds, even if you have excellent soil. First, raised beds warm up earlier in spring. They are less prone to weeds and you can control the quality of the soil placed within. The beds also drain well, which prevents soggy conditions in clay soil.
We decided on simple 4-by-4 foot beds. You can go longer, but I wouldn't go much wider or it's difficult to reach the center of the bed. You don't want to walk on a raised bed because that compacts the soil and adversely affects the growing conditions.
For our beds, I cut down 2-by-12 inch boards to 4 foot lengths. I stood them on end and nailed them together to form a box. By offsetting the corners, the finished boxes still measured 4 feet square exactly. I advise untreated wood because you don't want to leech chemicals into your soil. Cedar is an excellent rot resistant choice, but the boxes will still need eventual replacement.
Once constructed, simply lay your frame on top the bed area. Spread out a thick layer of newspaper to prevent grass and weeds from growing through, fill with soil and plant.