Might be a bit tricky to get hold of some originals, but they wouldn't be too tricky to make, basically, they're just a couple of pieces of mesh with two holes for the DZUs to go through.
If you can't find any originals, I would have thought all you would need would be about 8" by 6" of mesh (for a pair), some tin snippers and a drill (So says the DIY expert who spent 10 minutes trying to drill through a kitchen work-surface before realising the drill was in "reverse"
)