I've been writing the vector generator in VHDL for a spartan3e on a nexys2 board. The x/y/z are controlled by (hastily put together) R2R DACs. It's an actual processor, fetching opcodes out of dual port RAM that can be modified via USB.
Early test of a raster to check draw speed of the monitor.
Wrote some custom software to use it for visuals at 8static. Hooked it up to a Tenma oscilloscope (great color trace and lighter than the tek!), pointed a VHS camera at it and ran the composite feed to a V4 - worked out really well! Mirroring effects look really neat and the camera sensor picks up the beam in a great way, used the Genesis to overlay some of my effects.