I know this topic is a bit old but I felt I had to share this asap.

I've found Frostmourne's id on the list.

frostmounre.jpg

Its entry is 36942 on the list. If you make a custom item and use that entry id for it it will appear as frostmourne ingame. It wont have a Question mark icon. it wil be clickable equiped. Will work with your abilities as the screenshot shows.

I'm going through this whole list and exploring the items. I'll prolly share them sooner or later. You guys should try out some those ids. A lot look really nice.