If you've looked at the VHO site then you should probably be aware that Germar Rudolf, who was acting as the organizational brains behind VHO, was kidnapped in late 2005 and shuffled off to trial and imprisonment in Germany. He supposedly is going to be released in 32 days, but I wouldn't count on anything much more from him. Being suddenly seized and carted off to prison does have a funny way of changing people's opinions sometimes. I couldn't blame the man if he came out of prison sounding like a broken record replaying on automatic "Six million (hiccup), gas chambers (burp), extermination plan (fart), six million (hiccup), gas ..." In any event, that's obviously why nothing new has been produced. If Mark Weber were to get off his fanny he should try to get into print in English some works which Carlo Mattogno has written in Italian but which Rudolf clearly hasn't been able to publish (it's hard to run an independent book publishing business when you're locked away in the can). So instead of asking about why VHO hasn't done much, you'd do better to ask what Weber and the IHR are waiting for. Send them a notice and tell them to get some of these items which Rudolf has planned for publication into print now:
http://vho.org/store/USA/Late 2005/Early 2006: Germar Rudolf, Carlo Mattogno, Auschwitz: The Case against Insanity (ca. 300 pp.)
Early 2006: Carlo Mattogno, Healthcare in Auschwitz (in translation, some 130 pages)
2006/2007: Carlo Mattogno, The Crematory Ovens of Auschwitz (in translation; some 1,500 to 2,000 pages)
But don't hold your breath waiting for an answer.