Ganache alternative for "Nanaimo bars"
I would suggest a dark, dry caramel. If you make a dark caramel and add just a tiny bit of cream or butter to it at the end, it will be firm and dry (at least, as much as ganache is) and not "sticky", as you say in your question.  The trick will be adding enough butter or cream that the caramel remains pliable, but not so much that it is sticky; you may have to experiment some here.

A dark caramel will also add some bitter notes and contrasting flavors that would otherwise be missing in the chocolate-free bars.