Not really... The amount of CPU time it would take to process that large file, plus pulling updates.. Imagine having to pull the signature from Symantec... Download a 2GB file at 30KB/s.....

Yeah they can provide patches to patch the signature.

There is no antivirus product released now.. Corporate or home world that contains every single signature of old virus. Why do you think we got hit so hard a year ago? with such an old virus. The AV makers determined it was long enough since the last outbreak and removed it from their signature db.

There are corporate level of protection, such as the company I work for. We process all emails for AV through a 35GB database :P of signatures.