I'm a little skeptical, but it would be really cool if he were to reappear. I don't doubt that he could hold his own against any of today's players...I wonder why he would go to Japan?
This seem's plausible to me, because the top GMs are experts in differentating an engines play with a humans. Additionally Short must be intimately fimilar with nearly all of Fischers games and would be able to spot the nuances of Fischers style. I think it would be nearly impossible to create an engine that perfectly imitated a World champions play in slow games, let alone in blitz.
I saw a guy last year on playchess named Fischer on Kaspy he had a GM title and his profile claimed he was fischer, I watched him play on two consecutive days. He only played games with increment and was quite slow, he reached a rating of about 2800 in blitz if I remember correctly, in almost all the games he was destroying his opponents and he sometimes played weird stuff like 1f3 2kf2.The second day while playing some GM he quit in a loosing position and I haven't seen him since. I was running rybka while watching the games and his moves were almost always engine's first choice. What i found weird about this was the fact that playchess had given him the gm title and I don't think he got banned he just stopped playing, I'm pretty sure it was some guy with an engine.