Interesting Concept!

@Ekuah @Major Templar With both of your help, I've made my smallest extending conveyor arm yet.

You can check it out here:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=292437641

@Cosmo619 I've got a bit of a design for you. I decided not to show the ship yet as I'm still working on it and sadly it's just not there yet. However, I can show you the design of the Piston system. It's got a good range, piston does not show, and is stable within reason. There is a bit of bobbing when you disconnect but that shouldn't be much of an issue. It's more of the way the pistons connect to one another and it's having issues holding onto each other when connected directly, this solves that issue. https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=292298767

@Cosmo
I 've uploaded a streamlined version here:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=292173475

@Major Templar Well honestly I probably was over complicating it but that's because I was trying to do something that hasn't been done before. I tried just connecting conveyor tubes to the front of the piston, but I couldn't get the reach I wanted without the piston showing, it wasn't very stable, and broke often. It would be a lot easier to make a smaller version once pistons don't flip out at me xD

Cosmo619, You don't have to have the piston stick out but can have the conveyor attached to the piston and have that stick out. I've been working on a few designs myself that do something similar and the only thing that comes out is just the conveyor/connector blocks. The piston is hidden in the housing. I just worry that you've over complicated it by requiring each connector to be on/off and having such a large housing for something that should be a fraction of this size. Once they've fixed a few of the piston issues I will link it for you and show you that you can get it to work, be stable, and not have to worry about all those connectors. :)

You have neglected the tiny fact, that pistons can transport items. So the connector row isn't necessary. I've made a streamline version of your design. Size: 1 x 2 large blocks (w x h). Can I upload it?

That's what I did on my last design but I think the actual conveyor looks better than having a piston sticking out

Why don't you have it just attached via the actual doors on the piston?