We investigate modifications to conventional multitone direct-sequence spread spectrum (MT-DS-SS) signaling to improve spectral efficiency or reduce receiver complexity, for high-data-rate systems with small processing gain. Our first modification is a reduction in subcarrier frequency spacing Δƒ , which improves bandwidth efficiency at little or no cost in complexity or performance. The second modification employs fewer receiver local oscillators than subcarriers, in addition to Δƒ reductions. Reducing Δƒ induces known intersubcarrier interference, which we remove using known (training) symbols and simple inter-subcarrier interference cancellation. Via both analysis and simulations, we provide example results that illustrate the attractive performance and throughputs attainable.