Is there any live cd that can boot a PC and give raw access to the internal disks via USB

I.e. I boot PC1 with this live cd, connect PC1 and PC2 via USB, and PC2 recognizes PC1 as an external USB HDD device

This would be so useful for pc rescue and virus scan purposes.
Easy to update virus definitions, and run a virus scanner in any OS on PC2.
Also much easier to run any disk rescue tool regardeless of OS and driver compatibility.

Is there any live cd that does this currently?

If not, how hard would it be to make one?