I don't know, but I had an Elk burger at Fuddruckers (which tasted oddly like chicken liver) the other day. That was kinda cool.
To bring it back, I would imagine that in order to supply a chain like Fuddrucker's, they would have to domesticate the Elk in some way. You know, raise it in a farm/feedlot kind of way.
It's only a small step from that to training one, so I don't know. Maybe.