Okay, my scrolling engine is nearly finished, just needs some more optimizations and some small changes.
It's pretty cool, I support different types of layers (tiles only at the moment but easily extendable to add sprite layers, etc), parallax scrolling, multiple types of tiles (MovieClip, Sprite, BitmapData which can use one tilesheet and an index to add a certain tile, and the possibility to add new types, ie supertiles), which can be mixed on the same layer, and a setting per layer to indicate whether to use cacheAsBitmap or not. Oh yeah, and it can load tiles/tilesheets from an external movieclips's library if desired. It's pretty fast, too.

I'm considering making this freely available in a few days, would there be any interest?