This app was mentioned in 5 comments, with an average of 3.40 upvotes
Voila. This might take a little getting used to how to make each shape, but it's perfect for space engineers.
You start with basic cubes, which you can slice on angles, creating slopes, or join with other cubes, which you can slice those to make ramped blocks. It's a little more of a hassle than having every armor shape at your fingertips but I've found it to be very helpful when I'm on the go and had an idea pop into my head.
If you use android you can use Qubism to build a 3D model of it. Takes a bit of practice to figure out the app but it's great for when you think of an SE build away from your PC.
Have you tried:
https://play.google.com/store/apps/details?id=jquinn.qubism.android&hl=en
Probably not exactly what you are looking for though. Pretty sure it was posted here somewhere before...
I recommend this app for designing ships on the go. Much nicer than graph paper for designing ships.