Scrolling the Dock as in launcher pro possible?

Try Zeam launcher, it allows this and the dock is easy to use, you can simply drag an app into the dock.

 

Zeam as braj said, or you could get LiveHome or ADW Launcher which has a "pullup" dock, I think I read in ADW that it's "unlimited" number of apps that can fit in there, you swipe up on the app drawer icon and it pulls up an alternate dock, same goes with LiveHome.

 

You are asking for an app that isn't a launcher to perform a launcher task.

Can an app simulate the dock while not being integrated into the launcher?

It would have to lay over the existing dock. In the end, it's probably more seamless to get a new launcher.

 

I don't think that exists. I would suggest talking through why LPP was slow for you. It's blazing fast for me and many others, so perhaps you can sort out an issue you were having with it so you can use the dock again? Just a suggestion, I'm sure we could help ya out.