It is possible to added additional pre-defined fields to the sandbox view. To do this, right click on the column headings and select "Configure Columns". However, this will not accomplish what you want as you cannot create a new field to add.
There is currently no way to attach a file to a configuration managment project or member. There are some other options that may work for you:
Add the compliance report as another member in the project.
Store the compliance reports on a shared location, and add a link to the location in the revision or archive description. Note that while you can add the revision description to the columns, only the first line is visible.
Link the member to a Workflows and Documents item, and attach the report to the item.