No active CV forums or boards that I’m aware of, aside from the ancient Naggers mail list. There’s a Yahoo Group that is still (barely) active and that’s about it. www.brainwashed.com/cv is still a good resource but it’s not updates as frequently as it was previously. The Greedy Eye website died quietly a few years ago. Kirk’s own page is very minimal and is pretty much just updated when he has new stuff on iTunes.
Honestly, we probably stand as good a chance of having a reasonable discussion here as we do anywhere else online. Considering that between the collected works of the Cabs + Kirk there are ~36ish years of material to discuss, so it’s really amazing there’s not a more active board SOMEWHERE out there. Alas.