I have finaily managed to setup a encrypted system!
in total, it has taken me a couple of days (trying to keep keyfiles on usb sticks, trying to do it on edgy), but in the end it took 1 hour 40 mins from a blank disk to installed, encrypted and updated! 
https://help.ubuntu.com/community/EncryptedFilesystemLVMHowto
i would recomend changing your kernel once you have X/K/Ubuntu installed, as everything will have to be decrypted/encrypted as it comes from / goes to the encrypted partitons… so a kernel more suited to you CPU will help! (but I’m not seeing any major difference..)
megamaced has a lovely post on how to do this! http://www.hardwareforums.com/getting-most-x-k-ubuntu-6-06-a-13488/#post87508
so anyway, good luck doing whatever it was you where going to do to my machine! 