I could see going either way with the horcrux hunt, a segment of the "five year later" epilogue or a sequel with Bill eventually figuring out just how close Harry & Ginny really are (mind you I can't imagine it would take him that long, he's not that stupid) and having a "discussion" with Harry (I can see Fleur interrupting if Bill tries to go too much "protective big brother"). Personally, I reckon it's going to be a long epilogue if it's done right but I can see that likely being easier to do than a full-blown sequel.