From what I know, there will be a PSC708 to complement the Philips Edge range. The card AFAIK will use the same ThunderBird Avenger DSP, but will have more functionallity. Maybe 7.1?
As on the PC Stuff website, Philips will also be releasing other new cards PSC604 and PSC605.
The cards will complement the PSC703, 703, 706, 708 and 602 (PSC 702 and 704 are out of production). All except the PSC602 use QSound's algorithims.
Philips are getting very serious in the soundcard market..... expect some action soon.
Cheers