This is information on the use and output of the option --build-order of the repoquery script.  

1. call repoquery as a script
2. use "--build-order" as an option
3. specify a package for which you want the build order

Returns:
1. a list of all recursive dependencies listed in reverse topological order (most required packages first and the package in question last).
2. if more than one package is specified as an argument each package list will be sorted the same way and then appended to the end of the list.

TODO:
1. I wanted a way to do this for a whole repository, but this is the one step closer.
2. I also want that the lists combine, not append to the bottom.

Example:
My test was this:

For source RPMs:
./repoquery.py --repofrompath=fedora-test,http://mirror.chpc.utah.edu/pub/fedora/linux/release/15/Fedora/source/SRPMS/ --build-order bash

For x86_64 RPMs:
./repoquery.py --repofrompath=fedora-test,http://mirror.chpc.utah.edu/pub/fedora/linux/release/15/Fedora/x86_64/os --build-order bash

You can narrow the resultant package list to include only the relevant RPMs by using the --arc=src or --arc=x86_64 respectively

Feedback:
Let me know how I can improve this functionality.  I am most readily available at [email protected]