possibility to override default sender address in email template

We would like to send quotes for a seperate serviceline/line of business from another domain/mail address. We created specific quote templates for this, however we can now only send these out from the default mail address. It would be nice if it would be possible for instance as a setting in the custom email quote to change the sender address.

Consolidated into: Email: let certain users send out from a default adress and others from themselves