Create new document default fields?

Hello, is there a way that I can create a default field that appears on every document that will then automatically be part of the default TVs? For example, the [*pagetitle*] is a default variable that can be used at anytime, I don’t have to create a tv specific for that. Can I somehow create a new field such as sub heading that will appear under the pagetitle field but will be accessible the same way as the other default tvs? I would use TVs but I would like to extend the amount of default fields in the manager without having to use TVs, plus I want them in order with the ones at the top of the document. I know how to write plugins that will create new fields in the document manager and send that info to the DB, however I am unsure how to register that as a default TV like pagetitle, longtitle, alias etc.

Thanks!

No. This question is why TVs were created in the first place.