No reply to your question yet so I'll attempt to answer.
The following is how ubuntu (amongst others I suspect) do it.
The boot partition is not encrypted so that the initrd file can be extracted with all the necessary modules needed to read the encrypted volume.
The second partition takes over the rest of your disk and has LVM installed so that you can have many partitions/swap. This way, you avoid getting a password prompt for each partition that it encrypted.
Whn you boot, a prompt apears for the passphrase, if successful, your tux will boot.
I'm sure something similar exists or can be made to work for Fedora... it is still a Linux after all.
Hope this helped.