The invention provides an improvement in suspendable structures and assemblies such as linear lighting fixtures/luminaires that are intended to be suspended from ceilings or other such structures. The housings of the assemblies are designed to include at least one structural member with prestressing in at least along a major longitudinal axis over at least a portion of the length of the member. Once the structural member is incorporated into the housing and overall assembly, the housing and/or assembly is substantially planar and uniform once the assembly is suspended, making the assembly both stronger and more aesthetically appealing. Other embodiments showing extensions to the invention are also disclosed.