What cabinetry considerations exist for an island cooktop?

Island cooktops require downdraft ventilation or an overhead pendant hood, each of which has significant cabinetry implications. Downdraft units need a 27"+ deep island carcass to house the pop-up mechanism and require a floor duct. Overhead hoods over an island must be sized 6" wider than the cooktop. The island base also requires a dedicated gas or electric service zone — typically a recessed pocket in the back panel — so the utility connection doesn't intrude on drawer or door clearance.