I just finished this last night and uploaded the first Windows builds this evening - now ready for people to try it out and feed back with bug-reports, extra feature requests, etc.
Based on the Ctrlr project, which is a framework for making VSTi, AU and standalone executable MIDI controller apps, the Virus Ctrlr allows you to program almost all of the pre-TI Virus ranges' synth parameters and many system settings from inside your DAW. It's great for exposing parameters - whether common ones like cutoff or 'deep' ones like arp clock division - to automation and offers what is hopefully a reasonably intuitive GUI for doing it in.
Such things have existed in the past, but have (as far as I can tell) been commercial products which have never quite lived up to expectations and mostly seem to have been left in dev limbo without critical updates and fixes. Well, this is open source and all my code's up there for people to see, tweak, improve upon, etc. If I drop dead tomorrow, somebody else will be able to pick it up 
What it DOES:
- behaves like a VSTi - as long as you can get the Virus' audio into your DAW in the usual way, you can use the Ctrlr to treat it like a VSTi without ever having to touch the hardware. But if you want to touch the hardware - like to get some nice smooth knob automation - just set the Ctrlr's input to the MIDI device that's connected to the Virus. The Ctrlr will merge your host's MIDI commands and make it all work (though you may have to try a few combinations of settings before you get it set up the way you want
) - allows automation of everything you'd expect, plus some stuff you wouldn't - you can sync the LCD display's contrast to your dubstep bass, for instance
- operates optionally in standalone mode, from the included executable
What it DOESN'T do, but MIGHT do eventually:
- act as a full sysex patch librarian, a la Virus Control. The guy who codes the underlying Ctrlr framework is working on this, and hopefully it'll be possible before too long. You *can* send a snapshot of all the Ctrlr's values to the synth and save those values on the DAW-side, which means if you work from an init patch and set it up carefully, you can have a flimsy sort of total recall...and you can even instruct the VSTi to do this on load (with any sysex ms delays you need), but it's all experimental so far. Hopefully this will come.
- handle Multis, part control and patch names. This is all perfectly possible, but fiddly and I haven't had time to do it yet. If there's a LOT of demand, I will.
- handle audio, lik the Virus Control does. Obviously. But not even Virus Control gets this 100% right, and a lot of people with TIs just use VC for editing and automation, but use analogue outs for audio...so if you have an older Virus and you use this Ctrlr, you end up on almost an even footing with all those TI users (only with slightly less polyphony ;))
Feedback, criticism and bug-reports are all appreciated. If the criticism is along the lines of "it looks butt-ugly", well feel free to make some nicer GUI graphics and send them to me - that's what Open Source is all about
Note: I made this for my Virus B (which has faulty buttons that I can't afford to get repaired - the Ctrlr has solved that problem and was my main motivation!). I've added an EQ section which should make it usable for the C, though I don't own a C to test it on. I have no idea how well it'll work on the A, but I'd love to hear from people who've tried it. There aren't many parameters I've missed out, but there are some...and if you can make a case for their being absolutely essential in everyday use, I'll think about implementing them.
Download from here: http://ctrlr.org/page.php?p=download
!