I really think this is a topic where there are two sides and there will always be people on each.
I understand what CFour is saying in that Corvette needs to retain its American Exotic appeal.
However, I have to say I like what is being done. I think the bottom line is we will be getting a better car. I also think the car's powerplant is far more important than a few body parts here and there, and the Corvette will have its own engine. Like someone pointed out, the F bodies had the LS1. I don't find it to be all that disturbing of a concept. And the shared frame is more Corvette's than it is the XLR's.
I read an article in the new Road and Track (I think) about the XLR. You know how magazines will pull out an important quote from the text and put it in a picture? Well, they had one that said something like "Much of the XLR's frame will be what we see in the new Corvette C6". This quote shows proper respect to the 'vette, and gives credit where credit is due. I wish I could remember it word for word, but it was definitely written under the context that the Caddie has CORVETTE'S frame, and it was a compliment to the Caddie in saying it is using a true sports car frame.
So I disagree that the general assumption will be that the Corvette is following behind the XLR instead of the other way around. The XLR is definitely mooching off of Corvette's reputation, and everyone knows it. I don't think it is that much of a mystery.
Brett