Actually, I got an idea: perhaps we could integrate this into $wabooru (Caption studio is a planned feature) and expand upon it (all file types, more fonts, etc). Not sure if it would be possible doe.
The guy who created it has it under an MIT license, so I could nab it and dedicate a new page to it for users to screw with until our studio is ready. I'll ask him about it tomorrow when I get the time and see if he's cool with doing that. I haven't tested it out myself, but it looks quick enough.