[DustyPorViva]

Copying tiles that have been already layed - Not yet, but will be. I've already accomplished this offline so I know how to.
Copying and pasted slected tiles - Will be easily done.
Copy, cut, and paste buttons - Also easily done. I'm going to add a toolbar to the top of the screen that has different tool buttons as well as the layer stuff.

As for multiple tilesets, it would be possible to organize them, I'm just unsure how to actually implement them in addtiledefs.