This discussion actually got me thinking and in an experimental mood, making me try to make subtitles for the recently-completed King's Bounty run for Sega Genesis by aqfaq. This is something I completely winged and almost certainly contains wonky translations and factual errors, and I don't currently have tools to manipulate subtitle layout (everything I have now is for timing and DVD subtitle purposes). I'll see if I can get some tonight or tomorrow and put together something better, but for the curious, here's an MKV link on my personal webspace:
http://www.nihongowned.com/Kingbtest.mkv
Embedded into it are three subtitle tracks, which are as follows:
1. English - Explains what the run does exactly (manipulates the game-winning item into appearing next to the starting location, beats the game in 25 frames by taking half a step and searching)
2. French - Translates the important game text, although I go a tad overboard, and the final text takes up the entire screen; I'll have to find tools so I can flush it into the empty space to the left. Also, the subtitles are timed to match the game's text timing exactly; if it's on-screen for 2 frames in game, the subtitles will only be on-screen for those same two frames.
3. French - Same as above, but the timing has been stretched so that the subtitles can actually be read.
This is purely a concept demo, and admittedly not a very good one since I need to change the font and text position so it's easier to read. This entire thing was done in about 45 minutes, which included encoding and compiling the video.
If enough people express an interest I can slowly start making similar English subtitles for the game text for Samurai Goroh's Final Fantasy V run, provided that I have Samurai Goroh's blessing and he's sure to finish/publish the run as he's working on it now. I can expand the text as he releases WIPs and, if all goes well, have the subtitles ready at around the same time as the run's finalization.