Hi Nibbida, Thereductor,
Well, part of my approach to understanding this is that vedana, craving, cliniging and becoming are causally linked (apart from the immediate experiential differences). Therefore I started thinking what in my experience shows a string of phenomena starting from vedana.
Therefore pleasant vedana (after it's loss) conditions the arising of wanting it more (immediately). This is craving and as you say, it not being satisfied leads to suffering. So my next question was what does craving give rise to which can be identified as clinging. My understanding was that it leads to longer term obsession with the object of craving. This ties in very well with the idea of upadana- grasping, attachment, clinging. The mind clings to the object. (Which might lead to wanting to experience it more and more, and of course prolong the experience). I see clinging as a partially hidden mental factor as we are all attached to various things now,but yet we don't feel it, until that clinging is challenged with a loss. It is not very apparent unlike craving which is very much 'in your face'. Strong intermittent cravings leads to a more lasting attachment/clinging to the object of craving.
When there is a long lasting attachment this then gives rise to thought at other times, about the object of craving. This is the next step in the string that I experienced. We might remember something particularly nice that we ate for example later on in the day, removed in place and time from when we originally experienced the object. This thought which arises in the mind has 4 mental components (vedana, sanna, sankhara, vinnana) and is experienced in our body (rupa). Hence the five aggregates (or a 'being') comes into ..being. This is becoming. If we are alive it happens like in the example above. Or if we die then then whatever energies that come into existence from when craving arises continues into the next birth where it needs expression/release.
This is my take in this in any case.