Well one of the things that irked me about sai when I first started using it was that you couldn't copy, scale,deform,ect...in a linework layer. I looked for a way, but didn't find anything useful on DA or anywhere really until I just gave up and stopped using those layers all together. Idunno if someone has answered that question after I stopped looking but I found a very simple way to do all that.

When you use the selection tool to select the are you wish to alter you'll need to the selection tab at the top of the window and select either (Select CP's in Selection) or (Select Strokes in Selection) depending on what you need to do. (to deselect just go back to the selection tab and hit "Clear CP Selection")

Or the alternative is to select the "Edit" option in the layers brush dock (Make sure it's set to Select/Deselect) then you just right click and select the nodes that you want to alter. (Right click to deselect)

Remember though that doing it this way is only good if you want to select the nodes. If you want to select the strokes for example maybe you're doing realistic fur like what I was doing when I found this you might want the strokes of a portion and not for it to just cut off the node at the end of the fur tips.

Also if you want to rasterize a layer so that it's a normal layer with all the brush options just select the nodes like I mentioned, copy and paste it to a new layer. Then just create a new layer below it and merge the top one down.

Hope this will help someone cause I sure wish I had this info before :3