Open your eyes...
Have you contacted the company for these? - My understanding is that buying limited edition cards that are up for sale on Artscow would be - to be simple stealing.
Try eBay or contact the company.
Nope. The promo cards are posted on BGG by Greater than Games specifically so people without the promo cards can create their own personal copies. I don't know why they would encourage people to print their own but frown on paying Artscow to do it for them. As long as people aren't selling these unofficial copies for profit, there's nothing immoral/unethical about this.