I'd love to help you with the aesthetics, Bruce, but I have no taste. Someone like Ryan Freeze, OTOH, could take your current lined ponds and get them in "Better Homes and Gardens."
It sounds like you want this pond to have some of the aspects of the kind of shallow, easily drainable ponds often used for aquaculture of stuff like prawns. Maybe those types of ponds hold some answers for you???
Bottom drain in a lined pond may be the hardest part.