I've only heard a Headphile modded CD3000 at a meet (twice, actually), but I can say that I know I don't care for it much. Both times were out of a PPX3 Slam. The midrange sounded off, and something about the tone or timbre just sounded wrong to my ears.
As you've probably seen over in the build thread at headwize, mine isn't at the moment. Well, the amp itself is pretty damn quiet, but I get some noise from my source right now. I think I'm going to change the gain on mine to 2 like yours...should still be enough for balanced HD650s if I decide to try it.
My balanced Beta22 is mostly done, but I just need to finish my stepped attenuators for it (waiting on resistors). I'm balancing the D2000
-edit- I was thinking of using two Sigma22 boards, but only ended up with one. Still sounds great, though.