These things are happening all around the USA, at Vietnamese organized event. I suspect next New Year (in February 2013), that you'll hear more about Viet Khang at all Vietnamese events. It's a big deal.
One of the best, and most professional, music that come across my eyes is Asia Entertainment #69 "Tác Giả Tác Phẩm". The 2-disc DVD and Bluray just recently came out in late April, early May. Track 11 is the "Free Viet Khang" tribute, with covers of his two songs, "Việt Nam Tôi Đâu" and "Anh Là Ai", as sung by Đan Nguyên, Lê Quốc Tuấn, Hợp Ca Asia and featuring five-year old drummer Ngo Minh Ky.
Like the Paris by Night series, these Asia releases are produced and recorded live with a live event director and video switcher and live editor. It's incredible, especially considering that as soon as the show is done - the video is put directly on DVD (and recently Bluray). I don't know of another organization with the speed and flexibility of this company.
Anyway, the next Asia Entertainment show is #70 and will be taking place at Turning Stone Casino in Syracuse, New York on June 17th, 2012.