User blog comment:Thedoucheinthenorth/Can someone help me out on this?/@comment-5087679-20130120151104

I believe the article for the Fur-Trimmed Cloak confirms your suspicions; you cannot obtain it if you have destroyed the DB. She will remain permanently essential, and cannot be pickpocketed utilizing Perfect Touch while she is essential.

As far as I understand it (being a PC player), Xbox 360 "modding" is possible. In practice this involves taking a save game from PC and transferring it onto the Xbox via a USB stick and a console modding utility. This essentially allows you to do anything you could do on the PC with console commands, then simply play the save on the Xbox.