According to information from Examiner, Final Fantasy X HD has been worked only slowly since the first half of 2012 but was officially announced earlier at TGS 2011. Presented during this morning's Japanese live-stream, series producer Shinji Hashimoto revealed the PS Vita version of Final Fantasy X HD.
As I personally don't understand Japanese, I can't tell you what he says in the video that you can see below but when the opening ballad of the game comes on all sorts of memories of that game come rushing back. For those interested in finding out if the game will be available for any other device, it will be coming to the PS3 in HD but no release dates or prices have been announced yet.
Update: The original clip I found was 480p but I found a 720p clip that you can see below.