I use leftover arms for the one not holding the gun. The reactors have to be mirrored, as well as the torso. I used someone else's 35mm base but it's too high (https://www.thingiverse.com/thing:2490080). The whole model is a work in progress, there are several details that would need adjustments but I still like how they came out. I also wanted to test a paint pattern on an inexpensive model.
The editable model is here: https://cad.onshape.com/documents/ebec87f64a125a3638f8b7b7/w/a20026b561c99b48b754c54e/e/d1514a027de05801c918b625
I didn't really clean it up, and as mentioned it's a WiP. Knock yourselves out if you want to fork it.
2018-05-20 Edit: Here's a second version. I mostly modified the reactors, pulled the torso up by adding vertebra, and adjusted stuff here and there. I plan on using lychguard arms to make Destroyer Lords, I'll post pics once my printer is back (broken glass). It's version V10 on Onshape (see link above).
2018-06-17 Edit: Added better base and removed obsolete pieces. Still need to redo the gun to make it look like the original. This custom gun doesn't look so good and it doesn't print very well.