I am of the belief that just about anything in any format can work, so long as the words themselves prove interesting, original, or in some way moving. I am a verbal person, and I can enjoy reading a speech almost as much as hearing it. I get to imagine the nature of who is giving it. Or where they are giving it. I also like the idea of memoir. Wherein people can essentially giving speeches in a vaccuum. I think that just because it is not done often, or doesn't sound like what we are used to, that doesn't mean it won't work. Doesn't mean it will. But whatever sort of take we have on something, if we keep the concept of evoking an emotional or at least a memorable response in the reader as our goal, the sky is the limit as far as format.
Poe stories are good for knowing monologues as well. Stories like 'The Tell-Tale Heart' are excellent examples of what you're describing.
Thanks again for the comments, @EdFromNY: Yeah, I can understand that is a definite possibility and one of the main obstacles I'll have to overcome to pull something like this off. I guess the only way to find out if it'll work is to just do it, so I'll keep at it for the moment @TyUngleBower: I am of exactly the same opinion. The idea of a memoir is intriguing, I'll have to look into that some other time @Gigi_GNR: Thanks very much, I'll check out some of his stories when I next get the time