I'm trying to build a set of 'poons, and I need Petzl heel pieces and linking bars. I will buy the whole crampon if that's what you've got. Must have conventional lever closure (no sidelock thingie).

So who's got potentially worn out crampons they'd sell for essentially parts value?

AFAIK all current Petzl crampons can share heels. Older M10's used a screw to adjust the center bar position; I believe I need the spring clip-type adjustment style.