Even though you may be out of your 30-day window from VA, your credit card should still give you at least a 90-day period to contest the charge. Additionally if this is an established defect, it will be covered under the original 30-day exchange warranty. Contact VA to get yourself on record to show good will to work on the problem from your end. They may not respond, but you will have that as evidence later.
I have contested my credit card charge and recommend that anyone who is affected by this problem does the same. It is a slow process (up to 10 weeks), but the more people who do it, the more likely something will get done about all the brightness issues. Credit card companies are the strongest ally we have at this point. They are on the consumers' side and in my experience always side with the consumer if there is reasonable evidence of defect or lack of service (which we have plenty of both in this situation).
Also, please contact Panasonic if you have not done so already. They need to continue to understand the magnitude of these issues. If you're feeling especially ambitious, contacting consumer groups would be helpful, too.
Although Panasonic may be working on the issues, they are not keeping their customers up to date. Keep making noise. If they care about their customers and future business they will respond.