I read this without realizing it was a well-historied thread. My comments may be duplicating, but it's what I do when I find myself with a set of chords that I like. First thing I do is sing/hum along with the chords, allowing myself to explore octaves, harmonies, quarter tones, whatever. I guess that's the improv angle someone else mentioned. I tend to become obsessed with the thing I'm working on at the moment, so I improv like this everywhere, for at least a week, maybe two, before I try to add more structure. I sometimes will write a melody down, if I feel that's helpful. I also play with flatpicking/fingerpicking, key, tempo. I play around with the transitions from one chord to another. Usually, there's a "distance" one travels between one chord to another, and it simply takes practice to hear the possible steps. I'm typically playing around with lyrics about this time (though not always), so vocal phrasing intersects with melody voicing. I write down as much as possible or document what I'm doing in some way. I don't use a tape recorder because I've never owned one, which is a disadvantage, I think. I sing the melody of the moment and then I try harmonies, sometimes the harmony line evolves to become the melody line or vice versa. I have one finger-picked melody that's probably 15 years old and I've just added lyrics--in that process, the melody I fingerpicked has changed slightly. I'm not as knowledgeable about theory as I could be (that's for sure)and my tendency is to use improv as my primary muse. Don't know if any of this is helpful, but good luck.

blt