We are considering implementing a process to provide our colleagues with a "backup" laptop to ensure business continuity in the hopefully unlikely event a ransomware attack would impact their hard drives.  We have discussed everything from providing two systems, with one remaining "on the shelf" to having backups ready to deploy (which would include shipping for remote colleagues). Obviously each of these scenarios are without challenges and I'm curious if anyone else has implemented a similar process and would be willing to share some suggestions and/or lessons learned?

Yes, VDI (Virtual Desk top) is the most secure, efficient and cost effective solution. It has matured a lot in last few years and with availability of large NW bandwidth it is seamless. You can opt for multiple options from Persistent to non persistent desktop on public cloud and go for access on any device from anywhere.

I think it is "easier" to have dumb laptops (i.e. without local data) than to plan 2nd devices for people to use in case of a "disaster" / emergency.
Also it's way more cost effective.

Have you looked at the use of virtual desktops that can quickly be provisioned to provide access and would allow access from non-corporate devices in emergencies? Reducing the impact of any supply chain or shipping delays in getting replacement devices to the impacted colleague?