Help needed combining javascript for parallax effect.

[Vega]

Hello. I hope I'm posting this in the right place. This board was recommended to me recently and I've exhausted my efforts everywhere else, I think.

I'm making a website for my friend's project and I was hoping I could get some help here. The main part of it is a parallax effect like this one:

http://www.rleonardi.com/

There is a tutorial I followed to achieve a result similar to what this guy has at the top of the page. However, mine is supposed to be a scene that moves continuously. I want to replace the function that makes it move left and right with the movements of the mouse with something much more like this:

http://scripterlative.com/files/cursordivscroll.htm

Essentially, I want to replace following every movement of the mouse with a continuous smooth scrolling affect in the direction, right or left, where the cursor is. Even if the mouse is not moving, the scrolling would continue. I would also prefer if I could keep all of the image layers of the original parallax without it slowing down or making the scrolling too choppy. Does anyone have any insight into how I could achieve this, please?

One more thing I'd like to be able to do is to make certain images appear or disappear when you get to a certain point in the scrolling.

Can anybody help, please? Thanks in advance.