It sounds like you should change the boot order to move network boot below disk. After a system is provisioned, it still boots from the network. Once the system is told that it has been provisioned, it then changes to boot from the disk.
After booting your provisioned build without network connectivity, run dmesg, pipe the output to a file. If you can't see the solution in there, post it and I'll get some CG gurus to check it.
We've built & provisioned RHAS3.0 here, and it works fine, but we haven't tried booting any of our servers without network connectivity.
Turned out that some people requested an RPM installed (EMC NaviAgent) that was causing the problems. We've since removed that from the build and all is working well.