This is a complete redesign of the original N3DS Charging Dock I made. I never got around to it, and after learning a lot since about 3D printing and designing, I decided I'd give it another go from scratch. The result is much more efficient in terms of space, and (in my opinion) looks a lot better.
This has not been tested yet. I would recommend printing the "Registration Test" files first, to make sure that everything fits well. This was designed for the regular sized New 3DS. It should probably work with the XL version, since they basically have the same configuration for the charging ports.