This was an idea that I have been contemplating for a while, since Transactions – the alternative to Lines– does not capture any transaction specific fields and custom fields, which could be necessary for some reports.
I didn’t place this under ideas since there seems to be a lot of ideas at the moment, which are not a priority for development – at least not at the moment what with the electronic invoicing taking precedence.
Anyway, I will place this under ideas for now, however, that doesn’t mean that it will be implemented any time soon.
I think what needs to be done here is making lines more resemble lines as they are typed in or viewed on invoice, not individual general ledger transactions.