ThinStation is an open source thin client operating system based on Linux, maintained by Donald A. Cupp Jr., that supports the most relevant and commonly used connectivity protocols, both proprietary and free. For example SSH, Microsoft RDP, NoMachine NX, Citrix ICA, Redhat Spice and 2X ThinClient.
It can bee booted via PXE or installed and booted from local drives, with minimal hardware requirements.
Its free and available to download here.
