I Know, I wasn't being serious. I doubt, however, that the recent performances of M6 were just 'rehearsals'. In addition, I'm not convinced that waiting to use the Musikverein is such a great idea. The Musikverein may sound great in a live performance context, but it just doesn't seem to record all that well.
In addition, why would anyone want to record M2 in the Musikverein? It has too little space for large choruses and its baroque organ is way too under-powered and 'wheezy' sounding for Mahler. That's just my opinion - hopefully I'm proven wrong (and yes, I've been in the Musikverein numerous times).