For not thinking out of the box and considering loading a stripped down version of XP to only boot\recover a NTFS operating system. I guess being in the business as long as I have, I've never had the need to see if I could build a boot\XP system on a 256MB thumb drive or had the need for it when it takes just about two minutes to swap the drive into a system with a working and stable OS already installed with virus protection.
This is an example of it can be done but very impractical reasoning for doing it!
In all honesty, Bart PE is a stripped down/modified version of the Windows Pre-Instatalltion Environment (PE) that MS provides to OEMs. The PE disks have a lot of drivers that can be removed if the hardware support (things like hard drive RAID controllers, misc sound and video cards, etc) is not needed.