We were running some services on a stack of older Dell servers with mostly identical hardware. The RAID controller and mainboard on one of them let the magic smoke out. We (a sysadmin team of three) promptly decided to move the RAID array to another unused server in the stack in order to avoid a lengthy reinstall and manual restoring of daily backups – this happened before the almost-one-click provisioning of devops and virtualization tools was the norm.
The other server lacked the RAID license dongle that was on a pin header on the mainboard, so we just tried to cannibalize it from the server corpse that barely had stopped smoking. The new mainboard promptly rejected the license because the service tag differed, and the only way to change it was to install Windows 95 or 98 and run the tag changer tool. In addition, we had to downgrade the controller firmware to match that of the old one. One nightlong unattended rebuild later, the server was up and running the next morning.
When we upgraded the server hardware a bit later, we migrated it over to mdraid and haven't had any problems with hardware failures since.
Moral of the story: If you are depending on certain hardware features, you need to have a cold spare available with identical hardware and firmware. If you cannot afford one, it's better to either use a software implementation, have a really good service contract with the vendor or just let a VM provider take care of your infrastructure.