1. An ultrasonic diagnostic scanhead comprising: a scanhead enclosure; an array of transducer elements extending in at least two dimensions, located in the scanhead enclosure, and exhibiting a plurality of groupings (patches) of localized elements; a plurality of microbeamformers, located in the scanhead enclosure and coupled to the patches, each of which acts to beamform the signals received by the elements of a patch to produce at least two differently steered receive beams (multilines) from one set of received echo signals.