In my experience, a person asking to have a skin made just for themselves is only willing to pay what a single skin is worth to them. That's somewhere in the $5 to $20 range. When a company commissions a skin to use in their application, or to promote their product, they are willing to pay waaaaaay more. That's because, for them, the skin adds value to their product and increases brand recognition.
For me, the skin author, it takes the same amount of time to make a skin, regardless of who it is for. So do I want to spend all that time and effort to earn $10, or do I want spend the same amount of time and effort to earn waaaaaay more? It's pretty much a no brainer.
If I didn't have any commercial work to do, and had some spare time on my hands, I might consider it. But I'd probably just tell them to keep their 10 bucks. More likely though, I'd rather just make a skin in my free time that I want to use and share on WC. Or, I could develop a whole suite of skins and sell it for $10. That works because lots of people will pay $10 for it, rather than just one person.
Basically, I doubt a single person commissioning a skin for personal use from an established skinner or studio would ever happen unless they were willing to pay a rediculous amount of money that was on par with corporate clients. Also, most of the individual requests are for skins related to copyrighted material that doesn't belong to the person requesting it. Corporate clients don't have that problem because they hold the copyright on the subject matter.
