As floppy disks are a thing of the past, a simple utility to save and restore the MBR seems tougher to find. It should be able to run in a Dos box so when you boot a WinPE based CD you can run the exe straight from a USB key or whatever. I found one called HDHacker, but it's implemented in VB. I can't figure out how to add my disk drivers to WinPE so I don't really want to add the hassle of adding VB run-time on top of it. (I can, however, load my RAID disk drivers manually once the WinPE is loaded using Drvload.)
If anyone knows of an already existing one that isn't stuck away in a Dos boot image I'd appreciate it.
Right now as a stop gap I'm using the trick of a single file in a "dummy partition" and backing that up with Macrium Reflect. At the end of the restore I have the option to write the MBR from the backup to the HD. It does the job, but it's kind of a silly way to do something so basic.