Is this under hard acceleration or gradual acceleration? On my previous '98 coupe, when its rear shocks were worn out, trying to burn a little rubber resulted in pretty bad wheel hop, with small "chirps" when the wheels were actually contacting the pavement. I didn't really notice any pronounced suspension noise when this happened-- only that the rear wheels were not in full contact with the pavement.
One other thing that comes to mind: When I had the shocks replaced on my '98, the mechanic didn't get the upper part of the left-rear shock tightened all the way, and it made a very noticeable "ticking" sound anytime I went over a bump. Doesn't sound quite the same as your issue, but it's something you might check.
Well, I'm no mechanical expert on these cars (or any cars, for that matter). I'm just trying to help you narrow down where the problem might be and under what circumstances it occurs. From this point, I would try to find a dealer (or non-dealer mechanic) with a good reputation for working on Corvettes. Get them to drive/ride in it with you so you can point out the noise, then have them lift it up and inspect it. I'm not at home right now, but when I get home, I'll also look and see if the service manuals mention anything like this...
Good luck!
Fred
