Thanks for the suggestions. Good idea to not super glue the backpack to a model, especially if my concern is
WYSIWYG. Should also be relatively easy to find some backpacks, either on Ebay or third parties. My main concern though is finding models that look the part.
As mentioned I already have this model. I actually found a second one while rummaging around amongst my spare miniatures box:
I also have a Raging Heroes model which fits the part:
I'm not a big fan of this model but she does the job. Don't really want to buy 5 more of this model though.