Is it possible to customize the status field in order create additional states?
This would probably require a change to OmniFocus’ database structure. We probably won’t see it in the next few months. But your best bet is to e-mail feedback/feature request to Omnifocus@omnigroup.com and that should add this into the feature request database.
Currently, I just use the notes section and add a “tag” such as
or some other status label. Then I use the search field to look for that tag. You can also save a perspective with the search text to find these tasks.