Oh, I love Don Covay as well (but only have a best of)...
if you like Don Covay, i recommend:
Solomon Burke- any comp of his stuff on Atlantic from the early-mid 60's
Bobby Bland- 2 steps from the Blues
Gene Chandler- the Live album from 1965, can't remember the name, but as much as love Curtis Live!, this (along w/ JB Live at the Apollo 1 and Bobby Womack's "The Womack Live" ) are the 3 best live soul records ever...
if you like Doris Duke, i'd suggest a comp of Laura Lee's Chess era recordings, same for Etta James ("Wanted: Love no experience neccesary" and "Tell Mama", respectively are tracks to look for...)
if you like Alan Toussaint, get any cheapo Lee Dorsey comp that has Get Out of My Life, Woman, Ride Your Pony, and Everything I Play Gonna be Funky...
also, that Soul Jazz new orleans comp from a few years back is def another good record if you dig Alan Toussaint... "a break in the road" by Betty Harris is a nasty track...