Hi,
If your planning to install the redhat system u've built with custom kernel on 100 system's, you dont have to build a distribution.
All you need is software [eg. Norton Ghost or) G4L (
https://sourceforge.net/projects/g4l) ] which can copy the image of one hard-disk onto any number of hard-disks, provided all the 100 systems are having the same hardware [eg. video card, soundcard, ethernet card.... ] (or) the kernel you have compiled has support for all the hardware you have.