Visibility in report view to see if a quote has a task assigned to it.

We follow up on all quotes over a certain value. Every day the account managers set a task date against the quotes for the customers they are responsible for. Its easy to miss setting a task against a quote and we'd like to be able to run a report on quotes that don't have a task set, but unfortunately the 'task date' field isn't one we can select at quote level.... Could this be added in please?