they only list CTK-7000 (the 61-key version), as well as WK-6500 and CTK-6000, but not WK-7500. The release date given there for CTK-7000 is 10/2010. Looks like they've changed their mind and WK-7500 will not be released at the same time. The price given there for CTK-7000 is 63,000 yen (or 66,150 with taxes), which is roughly $750, however, a few sites offer it for 49,800 yen (or ~$600). For instance,
These sites also give the release date as late October. If I remember correctly, at these same sites WK-7500 was also listed a few days ago (don't remember the price, though), but it seems it has been removed since.
[This message has been edited by MChub (edited 09-17-2010).]