A general statement: lots of these have, surprisingly, popped out in the market along the last 3-2 years. I had a chance to examine two different swords firsthand and I don't have a definitive decision. They appear well made, good weight & balance, nice patina. But the large relative amount of them makes me wonder.
Those of you who sign with Facebook or Google+ may want to read my earlier article on such sword, here (I have some other papers there):