I read there were at least 2 vehicles of interest. Any news on that topic? It seems not likely to me that there is no trace of any kind there. Did they find the owners of the vehicles they've seen on the surveillance/traffic cams? If Jayme didn't want to go, then there had to be some fight until the person got her to the vehicle he/she was with. If she was dragged then there must've been some trace on the ground. In cases like this we're always told that "it is the perfect family", that "(s)he is a caring, loving child" only to find out later that things were not as bright as it was depicted by relatives and friends.
To me it just doesn't looks like a revenge kind of crime, because in those cases you either kill everybody or you leave the person alive to suffer. In this case Jayme seems to be the obvious target. I couldn't find any information about what communication devices had Jayme access to. This might be a good thing tho, since LE might be looking into it and they don't want to reveal too much. Then the Blaze Bernstein case comes to my mind where they released the information that he was talking to that garbage of a human being on Snapchat the night he disappeared.
They either have something to work with and don't want to reveal it, or they are just as lost as we are. It's hard to solve a crime when you don't see or can't find a motive.
I've read that some of you think she might get sold or something. No one in that "industry" likes high profile cases, or cases with too much media coverage. That's a huge risk for those involved and they usually (to my knowledge) don't take it.