Hi user_1000,
no, there will be no 64-bit build of avast 6, at least not initially.
Also, your argument about 16-bit software on 32-bit Windows doesn't really apply (for multiple reasons).
It's not like we're against a full 64-bit build, but frankly, it ranks fairly low on our list of things we want to do... (or we feel are useful/necessary).
Thanks
Vlk