My friend Panos has posted how to set up the Etsy Mini so that it will work on WordPress.com. Check out my sidebar!
Thank you, Panos. (Please go thank him, too.)
Update February 2012:
And *poof!* Etsy removes support for the flash widget. I’ve replaced the flash part of the text widget code with a cropped screen capture of the “new” mini after generating it on Etsy.