Thank you for bringing this up and providing the link to the dpr discussion. Honestly, I am surprised there hasn't been a replacement for the 5D before now. I got my 5D the day they became available in early October 2005 IIRC. It is a great camera and the least expensive way into a full frame dSLR. However, now that Canon lost it's monopoly on full frame dSLRs they have offer an update soon and continue a lower cost alternative to the iDs series other than a Nikon D3.
I truly expected a 5DMkII at PMA. Well on to Photokina with hope. I'm wondering if all the bad press on the 1DIII caused them to hold off and put it through another full testing cycle.
I just hope they keep the king of high ISO's.
Given Canon's past history of releases in February and August, and the roughly 3 year cycle for 'pro' bodies, I would expect any announcement this August, before Photokina. I doubt if their problems with the I series has any relevance. And they have got to upgrade sometime - that's the name of the game these days, upgrade constantly or wither and die. I don't think that the 5 series will disappear, though it might appear under a different label - 3 series, perhaps.
The faff about the book announcement in amazon.com tells me that the publisher expects an upgrade, and is putting down a marker; perhaps they have an NDA, but then perhaps it's only intelligent guess work.
Amazon regularly lists books due for publication months in advance - nothing new about this.