According to Kotaku, the planned big screen version of Voltron: Defender of the Universe has been sent back to the beginning. Reports over the years of multiple scripts have come out and occasional false starts about production, but it now appears that everything that has come before is being scrapped in favor of starting from the beginning again. News surfaced back in 2005 about making a feature film of Voltron with Mark Gordon producing while Justin Marks was brought on to write the initial treatment. Not unlike other Japanese origin pictures, this one was being transplanted to New York City and altered in several of its core storyline and character elements.
All of this has been jettisoned at this point and it appears that the original director slated for this, Max Makowski, is no long involved either. Movement on the series has reverted to WEP (World Event Productions) who owns all things Voltron related in the US and has mined this field admirably since the mid 1980's when they built the show around the original Japanese shows of Armoured Fleet Dairugger XV and Beast King Go-Lion. Both shows have been released in the US (or are in the process of being released) along with the Voltron episodes through Media Blasters. WEP has also made the dub series available online at YouTube here.
You can read our reviews of Beast King GoLion here and Voltron along with Dairugger here.