Svence,
Good luck with your projects. There are a few videos on cushion making on U tube that might be of some help to you. There is some info somewhere on sewing piping etc.
Here is one of a custom cushion video....
http://www.youtube.com/watch?v=DCADkbAqqMQ
Here is a video showing Sailrite machines
http://www.youtube.com/watch?v=JVctef6IRlo