The Official PlayStation youtube channel just uploaded a new FFX/X-2HD trailer which now includes an official release date.
Final Fantasy X HD & X-2 HD release on March 14th 2014 for PlayStation 3. Although the Vita versions are listed in the trailer, the release date, strangely, only mentions the PS3 version.
FFX HD includes a new epilogue called Eternal Calm
FFX-2 HD includes The Last Mission content and both games are the International versions.