"would seem a broker statement of shares or actual shares and a copy of the chap 7 would prove the loss well enough for IRS "
Not good enough. Since you still own the shares, even if the company is currently in BK, you still have the ability to make money if the company ever comes out of BK. The IRS will not allow you to have it both ways. You either book your loss or you have a potential profit in the future, in the eyes of the IRS.
Once you have booked your loss via a sale, you no longer own the shares, and are not still playing the market in the eyes of the IRS. NOT booking a sale and still doing a right-off leads the IRS to believe (rightly or wrongly) that you want to book the loss, but still want to keep the "investment".
As I said before, you can't have it both ways.
