Thanks for this thread - I've delayed replying because I wanted to read it to the end first and there's a lot of content there to keep me thinking!

To add my two penn'orth, though (which seems to be quite long, sorry): I've fairly recently started to have a go at singing ballads (because I love listening to them so much), and I'm working up to the 'big ones' fairly gradually by starting with shorter ballads (7 or 8 verses) or shorter versions of longer ones. I tend to look at as many versions as I can find first and put together 'my' composite version. Then I go and sing it in the shower, while I'm washing up, in my head when I'm falling asleep, in the car... for at least a couple of weeks before I even think about singing it in public.

I'm interested in the comments above about 'seeing a film' while you're singing. I tried to do that, and I find that it actually makes my performance considerably less engaging because it breaks my connection with the audience. What I try to do now is to watch the 'film' a few times while I'm learning the ballad, and then perform it as if I'm telling my friends about this great film I saw. I was also advised at one point to fill in all the peripheral detail in my mind - how old are the characters? what do they look like? what are their backgrounds? why are then doing this? I don't necessarily go through the whole process every time, but I do if I'm having any difficulty at all engaging with the story or any characters in it.

In terms of the melody, I don't tend to do much in the way of deliberate ornamentation but I think I do vary the tune quite a lot - I find it keeps the interest level up, unless you're specifically going for the soporific effect in one particular ballad. Another piece of advice I've been given is to leave the tune alone for a bit and speak the words as if you were having a conversation, and I tend to find this leads to both a more convincing delivery and some interesting rhythmic and melodic variations.