OK, I'd say that's enough.
Right now, avast! CD is what it is, call it a business decision if you wish.
Whether there will be a different version or platform, only time will show... but I really don't think it's a priority at the moment.
Technically, making a USB version isn't that hard - I moved my BART CD (3.0) onto a USB stick and it works. [OK, had to make a small fix in the code first, but I believe that's included in the last 3.0 beta]. As for Linux... I guess that would be an option too, but as I said, I believe there are different priorities now (such as releasing v6 of the ordinary Linux/Mac avast!).