A draft proposal for Fedora spins

Yes, if you are building packages locally you can use mock

http://fedoraproject.org/wiki/Projects/Mock

Fedora build systems, plague and koji take advantage of this. 

Fedora has specialized tools for building a spin. These is livecd-tools for live images, ext3
images or software appliances and pungi for regular installation images and revisor which is a
graphical interface that does either.  Refer

http://fedoraproject.org/wiki/CustomSpins

There is also more detailed information on how livecd creator works at 

http://fedoraproject.org/wiki/FedoraLiveCD/LiveCDHowTo