It's definitely an issue. There's been several reports of needle bearings being found in the oil. It seems to be most prevalent with the '07's. I found 4 needle bearings in the oil on my '07 at 5,200 miles and I know of several others on this forum who have as well. On other forums there are also reports of the same.
The cause is the rocker arm design. The end cap is coming off or breaking which allows the needle bearings to come out. It's been an issue for a long time, including with the C5. Harland Sharp can modify the stock rocker arms by modifying them to accept a c-clip, thus preventing the issue from ever occurring. However, GM has not yet seen fit to do something similar, if not identical, themselves.
If you find needle bearings in the oil, don't worry. The repair is simple: a new rocker arm will be installed under warranty. Some dealers may replace all 16 and others will claim GM says only replace the broken one. Some dealers may remove the oil pan and oil reservoir and clean them, others will do nothing but change the rocker/s as above.
There are 33 needle bearings in each rocker arm. Again, I only found 4. When some people have told their dealers this and asked what they should do if they find more needle bearings, the response was a shrug.
