I generally try to avoid the use of "with all due respect", because as you rightly point out, it implies anything stated previously by the other party is beneath contempt. I attempted to use the expression as a joke here, but if anyone uses it to me in a serious fashion, I reply by beginning: "With slightly less respect..." This used to piss off fellow middle managers during tedious meetings in my previous job.

I love the read off idea, although I warn you I can be exceedingly dull on demand. I once bored my wife to sleep (at her request, as she was restless) by starting a lecture on the history of concrete. She was asleep in less than a minute.

(In case you are wondering, I am no expert on the history of concrete. But know a few basic facts on the subject, as I once worked in a bookshop, and had a competition with another staff member to locate the most boring book, which included one entitled The History of Concrete. I think she won, as she managed to locate two other first-rate candidates: The Compendium of Pea Diseases and a lengthy tome reporting on the 1996 New Zealand welding conference.)