seems that nearly anything can be used to make starter around here, i know i've made them several ways, but always the homestyle way with common ingredients. these are some of my results
fresh squeezed lemon and orange juice, pinch of sugar, high gluten flour
corn mush, oats, LJ, pinch of sugar, HG
oats, raisins, pinch of sugar, HG
raisins, LJ, HG
wild concord grapes, HG
a few grains of yeast, HG, LJ
i've had luck with all of these. some take a few hours to kickstart, some take a week if not more.