I just took my Peco Junior for it's first outing today and was very happy. It's a relatively light weight monorail, but has some restrictions that need workarounds. It has limited swing movements: look at the front standard and you will see that it has a kind of slider slot on either side. So you can't tie this one into knots like you can with a sinar etc. The sliding back may be helpful - but look if it can be used in horizontal and vertical position! Mine came with a dedicated 4x5" graflok back on which you can only use rollfilm holders in portrait position - there is simply no room to rotate the GG with the holder attached and most modern rf holders are too wide to fit within back standard's space. We did a little remodeling en put an old Linhof international back on it that is a bit smaller than the dedicated back. With this, the problem is solved.
The normal bellows sometimes pop up on eBay but are a bit stiff, so even with a 150mm lens I find I have not much freedom of movement. Watch for a wide angle bellows, I found mine, a very tattered one, on eBay after three months waiting. Bellows can be replaced, but what is important are the metal bits with which it attaches to the camera.
Other than that: please give Plaubel a ring. I've had several contacts with them and they have always been helpful. There are still some parts available from old new stock, so it is worth checking out. Prices are very reasonable. A new knob only cost me 25 euro and they threw in free photocopies of the camera parts listing plus numbers (essential for eBay hunting).
Hope this helps. If you have any more questions you're afraid to ask Plaubel, lemme know.
Norm