I just received the July issue of Music Inc. and there is a full page ad for 3 new workstations. The PSR-S670 which we already new about and will be available right after NAMM in July and the 770 and 970 which the ad says can be preorded now for delivery later this year (it doesn't say this year but if they are showing pictures and letting us know about it now it surely will be sooner rather than later). The picture looks just like the 950 but I'm sure there must be new content.
I can see there is now a separate category for guitar and one for bass so I would think Yamaha has added many of the Tyros5 guitar sounds and perhaps the modeling of guitar amps too.
I called Yamaha to ask about this and there is no information coming from them yet. More to follow