Hello Tim
I have searched all my usual places & sites to try and find something suitable you could use, alas to no avail.You could keep an eye on the more 'toy' soldier sites if they are to be found anywhere they will likely be on there.
The only other option open is to scratch build one using wire to get the shape and then draping it with tissue paper wetted down with water/PVA glue. If you use this method you might end up with a better result anyway!
Sorry I can't be of any more help
Good luck with your project!