Well, I can not directly answer your question, I can tell you that I've heard plenty of rumors. Here's what I've heard.
1)SRJV-19: "Guitar & Drums". This is supposedly the solution to realistic guitars on the JV/XP
2)SRJV-20: "Sample ROM". This is supposed to be an 8MB Flash ROM board to store .wav, akai, rdac and .aiff samples?
I can't say that these are true, but I overheard some music store employees talking about it. When I enquired about it, they said that they also heard of this through the grapevinve.
Anyway, forget about those rumors. What about the SRJV80-18 Latin Board. This was supposed to come out last year and I haven't seen one on display or in stock here in New York City.
The Infamous EPU.