Is a metaphysical theory of truthmakers possible?

Truthmaker theorists typically claim not only that all truths have truthmakers (Truthmaker Maximalism), but also that there is some enlightening metaphysical theory to be given of the nature of those truthmakers (e.g. that they are Armstrongian states of affairs, or tropes, or concrete individuals). Call this latter thesis the "Material Theory Thesis" (it is the thesis that there is some true material theory of truthmakers). I argue that the Material Theory Thesis is inconsistent with Truthmaker Maximalism.