I have a wonderful kitchen aid (European version) that a friend moving back to the US gave me. She did warn me however, NOT to make serious bread dough with it because "it was the cheap version" so even though it came with a dough hook it might burn out the machine.
So, be very careful to get a kitchen aid powerful enough to handle the job you want it to do - if you are seriously going to be making bread to sell, you may want to look into supply houses for the food industry and/or simply reviews of higher end kitchen aids on line.
The other, lower-cost but higher labor option is a large, hand-operated kneading pan which I got from Lehmans and other places sell as well. These were used by bakeries up until the 1970's and are still used in the third world today. They make about six loaves of bread at a time and are fantastic if you've got a good arm (or an excited 10 year old) to keep turning the mess round and round until the dough is just about ready to shape. I find it usually needs about 2 minutes of kneading afterwards to firm the dough up but not always.
Finally, there are some heavy-duty bread machines that you can use as a dough mixer (I do this) though most only will make about 2 1/2 pounds of dough at once; though I'm not sure a kitchen aid would do much more than that.
expatriate Californian living in rural Ireland with husband, dogs, horses. garden and many, many cats