I don't have a template, but I was thinking, maybe you could find a real safari hat? And the kids could share it (b/c if there is any lice going around, though!). Sometimes Oriental Trading has hats for (relatively) cheap. Perhaps you could order each kid one from there (w/ the parents contributing to the cost, of course).
Here's a link to the hats on OT. There are also some really cute jungle animal baseball caps. This might be good if you have any kind of budget or the parents chip in.