Remote X display for linuxcnc?

Yes, most still have a replaceable boot ROM as well as support for Intel's PXE or various other network boot environments.

I see what you're thinking... set up a headless PC with the necessary I/O for motion control and nothing else (maybe a serial console even) and arrange for it to network boot from the front end PC. That's actually the sort of scheme that many Linux based cluster computers use... they have a local disk for caching of data only, their main kernel and applications environment is downloaded at boot time via the network.

Wouldn't take much in the way of config on the "console" PC either... just a specially configured DHCP server and TFTP or similar, and the controller PC would load up its embedded code and take off, contacting the console over the network when it was booted and ready for work.

Hmm, more and more interesting.

I could see using Machinekit, or even simply a cut down linux kernel with a RAM disk plus maybe something like busybox to help debug remotely. Similar config to lots of the appliance linux servers, wireless gateways, and even tablet PCs that run Linux.

Without the full multitasking kernel and associated packages, it wouldn't need much hardware to run, using Linux as the kernel it would support pretty much all the PC hardware out there, even legacy gear and industrial PCs with ISA backplanes.