Aside from the fact Ichigo's Original Zanpakuto was Zangetsu. I now believe that the one he is now carrying is not Zangetsu as it was never stated if a Zanpakuto can change it's Shikai's form after Release. From what was seen in the last few Chapters (Isshin, Urahara and Rukia's Meet / Urahara and Isshin walking with the Glowing sword that stabbed Ichigo) These factor out to the possiblility that the Zanpakuto that Ichigo is weilding my be Engetsu (Isshin's Zanpakuto). This wouldn't surprise me since Engetsu could do Getsuga Tensho and from the knowledge Isshin has The Final Getsuga Tensho. (Hence why Isshin didn't have his powers for the last 20 years. If anyone else finds this odd please comment this with your opinion.