One way of looking at the upcoming Canon product line is to posit that the order in which the flagships were introduced was flipped...
1) 1D mark IV was replaced by 1DX ...a faster lower MP body (yes it happens to be full frame and not APS-H)
2) 1Ds mark III is yet to be truly replaced...though canon earlier claimed that 1DX is that replacement...I think the rumored higher MP body (1DsX?) is the real candidate that is destined to occupy the slot left vaccant by 1Ds Mark III.
The anticipated higher MP body (1DsX?) could likely have ~35-45MP, lower fps, 1DX metering and AF, other 1 series perks, and if you buy into this hypothesis, we can expect the price range to be pegged higher than the current 1DX, at may be $7.5 K to $8.5K, not that far from its original predecessors. They may throw in a few bonuses like GPS and wifi...while pro's were never really dying for such features, they won't say no to it either if offered.
Whatever its final form, this new entry is bound to be a substantive body with an impressive feature list.