Shower baths give the best of both worlds when there isn't the room to put a shower cubicle and bath in the same bathroom.   A shower bath has the same length and width as a standard bath but increases in width at the shower end either as a circular shape (a P Shaped bath) or a square end (an L Shaped bath).  A screen is then placed around the edge of this part of the bath to create an area that has more arm room to move around in for a shower but has the normal width for the rest of the bath.

Some manufacturers have taken this idea even further by creating a P Shaped bath with an infill for the extended part of the bath, this reduces the amount of water needed to fill the bath without reducing the amount of usable bath space, but yet still giving the maximum amount of space for showering (as all the room required is at the top not by the feet).