An implantable neurostimulation electrode interface and related system arrangements and methods are provided. The implantable interface may include at least a first stimulation signal channel for receiving a first electrode stimulation signal and a plurality of electrode signal channels electrically interconnected or interconnectable to a plurality of electrodes for neurostimulation. The interface may further include a router electrically interconnected to the first stimulation signal channel and to the plurality of electrode signal channels. The router is controllable to directly route the first electrode stimulation signal to different first successive sets of one or more of the plurality of electrode signal channels. The router may be adapted for routing the first electrode stimulation signal as an electrical current signal, without modification of the signal. Stimulation signal generation componentry and power source componentry may be located remotely from the implantable interface. Such componentry may be selectively interconnectable to and disconnectable from the implantable interface.