From the start, I must say that some heavy assumptions are being made in this analysis, and I do understand these shortcoming of my analysis, this must state that this is for speculation and fun ONLY.
Taking the price of the historical "big brother" of the 5D line, the 1Ds (due to FF) and determining the price index between them over three generations of cameras, one can estimate an index based price of the 5D. Due to the fact that the 1DX has an MSRP of $6800, and staying true to its historical index, the next gen 5D would be priced at $2714. This is assuming that no other factors are involved in pricing (features, tech, inflation, exchange rate, etc.).
If we strictly take into consideration the current price of the YEN vs. USD over time (as some on this forum are prognosticating), we can expect the price of the 5D3 to properly reflect the historical prices of the 5D (with respect to the 1Ds prices) at $4064 adjusting for ERs. This would be the MSRP IF Canon wanted to continue the exact margins/index as the last generation of 5D/1Ds.
HOWEVER, I repeatedly hear justifications for price increases of the 5DmkIII base on solely exchange rates. I believe that this is a misnomer and not the driving MSRP factor for canon due to the fact that the MSRP of the 1DX was set at $6800! The price of that camera went DOWN compared to its last generation even with a YEN increasing in value by 50%. I do understand that the 1DX is not a true offspring of the 1DsmkIII, but with the combination of the two lines and addition of new features to boot, I believe my point to still be valid.