While I had a very basic idea of the list I was planning to run with my Freebootas, I didn't have the specifics worked out. While going through the codex, I decided it would be a good idea to have Grot riggers on my vehicles. Since I'm trying to make this army as WYSIWYG as possible, I started looking for a way to model these.
I think these Grots in backpacks come with the Loota & Burna Boyz kit - I bought five of them from a bitz seller, one for each of my Battlewagons.
I trimmed off the mounting tab on each model:
...and I mounted each one in the rear compartment of the Battlewagon, next to one of the Orks manning the shootas:
Overall I think it's a cool solution that gives a little extra character to the model!