Yes. Use SuperDuper to clone occasionally to a laptop-sized HD and you can probably get the restore time down to "how long will it take me to open up the machine and slide in this backup HD".
Such a backup might not be especially fresh, but once it's up you can sync over files from a fresher, automated backup.
(A complete Time Machine restore of my laptop over Firewire takes 2-3 hours. I sleep better at night, knowing this.)