In Little Rock there is the Whole Hog Cafe that's well worth a stop. There's also Sim's and their Mustard sauce that many like but I've never been a fan of since they cut off and throw away the bark.
In North Little Rock there is another Whole Hog that's as good as the original in Little Rock plus they have a good version of Shack Sauce.
There's also Lindsay's Hospitality House that's pretty good.
Further East off I-l40 in DeVall's Bluff there is Craig's BBQ. One of my all time favorites.
In Memphis I'd avoid Interstate BBQ and even more so I'd avoid the Rendezvous. My recommendation is Central BBQ on Central Ave.