The top cobbled classics don't end in sprints other than occasionally the two you mention, no, however there are some semi-Classics and quite a few decent one-day races up there that can, and do, end in bunch sprints. The first that springs to mind is Kuurne-Bruxelles-Kuurne, the new version of Paris-Bruxelles (the old version too), GP de Fourmies (that's 1.HC), Rond om Leuven, Nokere Koerse, Dwars door Vlaanderen (though that's getting better on that front), GP Pino Cerami, Halle-Ingooigem and so on.
Plus you have the potential for stage wins in stages around the area - races like Eneco, Ronde van België, Driedaagse de Panne-Koksijde, Quatre Jours de Dunkerque, Tour de Wallonie, World Ports Classic, Ster ZLM Toer and the Tour de l'Eurometropole - all have some flat stages that these riders will have the chance to pick up some good points.
I know, Sky aren't going to do all of those, but there's plenty of opportunities there of picking up wins and good placements in a lot of races for a versatile sprinter. Just ask Tom van Asbroeck.