I have indeed written a fair bit about it and quoted good write ups by others too, especially one by Matthew Davis (see link below).
I am sure people are sick of reading me banging on about pricing and rubbishing the nonsensical "X times materials cost" formulae that seem so popular, but so few people seem to have any idea how to run a business. What you have written Melanie is a good summary of the many factors that need to be taken into consideration.
Matthew Davis's Article - How To Price Your Work