Don't think you're totally correct on this, enchantedrythm. The Stax 45 cut of Eddie Giles "Losing Boy" certainly was released on the Kent LP "Kentstax", which, as you say, included Margie Joseph's "One More Chance". That lp did not, however, feature "I Just Can't Get Over You", which, to the best of my knowledge, remains Japanese only.
I agree with Andy Dyson about Rance Allen. A phenomenal and unique talent. I find it odd that no-one's mentioned Johnnie Taylor yet. I concur with the people who've mentioned Darrell Banks' name. It's funny that, while he's thought of as a god in Northern Soul circles, he remains cruelly undervalued by the rest of the soul world.