Bushwhacker makes several different sizes - and they come in other colors besides black. I'd prefer yellow for visibility - which they do not make - but I suppose you could always use a yellow raincover.

Back in the day, most all rear panniers had the angled front edge to minimize heel-strikes. In fact, the used '70s-vintage Cannondale bags I just picked up are made that way. My old set unknowingly got sold at a garage sale... Trying to piece together a complete set in one color thirty years later is an exercise in futility!!!