My goal is to send 4 unique video signals and midi control to simple motors, and to build a sequencer in vvvv. Is it possible to have multiple renderers, each being fed independent information and then each sending to different destinations? The content will be video with a few sequenced effects. I am also planning on interfacing with pd for multichannel sound output. Is all of this possible with vvvv?
yes. boygrouping would be the way to go. boygrouing allows you to program multiple machines from one server. be prepared to have five machines for the setup (like one server + four clients for each display). this will give you lots of cpu and gpu power for each vga output, and you can do amazing effects. as pcs are basically cheaper than professional video players, this is usually a very effective solution for media installations.
in case you want to reduce the amount of machines you can try to experiment with dualscreen cards in span mode (like 2048x768 stretched over two monitors), or ultimately multiple pci express cards in one machine. another option are modern plasma monitors which allow you to zoom in on a section of your image - output 1200x1600 and have four plasmas displaying a 800x600 section each. similar things are available as standalone devices (eg the Quadra UDC400)
sending midi or rs232 to control motors is no problem.
exchanging information with pd via osc or midi is also no problem.