We have a new version of CBJUICE utilizing the CB API that we are testing. It allows delete using a CSV file. It does NOT all duplicate emails to be loaded. We have tested it in 1.5 and in 1.6 with a slightly patched version of CB. We will be looking to release when we have sorted out some menu options and when CB is completely integrated with Joomla 1.6
P.S. The new version allows you to export hashed passwords and move them to another site.