Okay, here goes. The Kelly JPG clutch is the violet(?) one you posted in the info thread. Just a short, squat kelly with a very small top handle. This bag has the most debth of all the clutches.
Lucy/Lucyndskywdmnds posted a picture of the Kelly Elan pochette in Kellybag's thread about Chamonix. Someone correct me if I'm wrong, but I'm pretty sure this has a thin leather band on the back to slip your hand through. No top handle. Not as deep as the JPG.
Now, for the Kelly Longue, I've never seen this one up close, but, to me, it looks kind of like the Jige, with quite a bit more width and less depth than the other two. I call these types of bags envelope clutches. All three have the signature Kelly belts and turnlock thingy.
HTH!