Can I allow users to choose what input widget a Drupal field should use on a node by node basis? This is a question I've asked on Stack Overflow but perhaps this is a better place for it. Apologies if this is seen as cross-posting...

I have a "transcription" field available within a content type in Drupal 7. Is there a way I can add a switch to allow the user to select whether that transcription content should allow tabular data input (via the TableField module) or whether it should be rich text/html?
In your content type definition, create two different fields, eg: data_tab and data_text. Then have a third field where the user can indicate their format, and use the Conditional Fields module to display the correct data input field.