I suppose upgrading the 8.10 box is out of the question?
1. physically remove the kernel module
2. put "nousb" in the grub kernel line
3. switch the usb system off in BIOS
... unless you want root to load the module with insmod.
I suppose you could also fiddle the rules so that only root gets read access to any usb devices loaded.
in /etc/modprobe.d/blacklist is what will disable the usb_storage driver in Ubuntu 8.10. I'm guessing a different driver is being used back then.