Ask HN: Live CD virus scan?

Hi everyone. I was reading about the recent AV news and I was thinking about my ideal AV product.

A big problem (IMO) with AV software is they run inside a running OS. I've been reading about some of the clever things that some rootkit malware does to hide itself away and the AV has to compete on the field.

What I'd like instead is to be able to boot the machine with a live CD and have it check out the files on the hard disk before any malware gets to run and hide itself away. The software on the CD would have to download the latest AV signatures and start scanning the dormant files without anything getting in the way.

Does such a service exist?

Many thanks.