arKos is a growing plugin collection targeting architectural design. at the moment it features a handrail plugin for creating all kind of handrails (and of course other structures, eg. fences or grids). see the gallery for some examples.
the handrail-object is a parametric object which takes a spline as a child and builds its structure along it. this structure consists of the following sub-parts. Each can be activated or deactivated. there is a container subobject generated which can hold the custom parts to make the reuse easier.