Node architectures which are being considered for wavelength-routed WDM optical networks do not provide a high degree of scalability with respect to the number of wavelengths in the system. In this investigation, we propose a new node architecture which allows new wavelengths to be added to the network without significant additional costs. We study the performance of such nodes in a network environment, and we develop a simple cost model for the network. We show that the proposed architecture provides a higher degree of scalability as well as significant cost benefits when compared to a traditional node architecture, such as the wavelength-routing switch (WRS) or a wavelength-selective cross-connect (WSXC), while also maintaining comparable performance in terms of blocking probability.