Since the original question was specifically limited to quarter-stocked underlever guns, the field for comparison is limited. Several Haenel and Diana BSA 'clones' would qualify, plus a few from Asia (only one of these I've seen in the flesh was a somewhat crudely finished example from India). If the restriction on stock style were relaxed, I'd propose the Diana 58 as the most elegant pre-WWII underlever of all.

Don R.