This looks like the new indoor ice rink they built for the Frozen Summer Fun or whatever it's called (next to Toy Story Midway Mania). It's quite pretty! I wonder if they'll keep it open for events like this.
Disney Event Group can get an ice rink for you at any location that would accommodate it (I'm thinking World Showplace Pavilion in Epcot is the only other one large enough, but maybe the Yacht & Beach Club's main ballroom could fit it).
No, you totally made a great point! I mean, if you do a private event inside DHS, will they let you use the Frozen ice rink while you're there? It's an interesting idea...