Can I create an OSX image to install after a disk format/7-pass
funny, i just did this the other day.

you can use disc utility to clone drives at any time (the "restore" tab, far right). instructions here: http://nyacomputing.com/how-to-create-a-bootable-clone-of-your-mac-hard-drive/

so the next time you wipe your drive, perform your fresh install of OS X (assuming current mavericks, 10.9.5) and install all your apps just the way you like them. when you have everything configured just right, use disc utility to clone the system drive to an external.

so what do you do next time after you wipe your machine, to get it all back to normal? using OS X's new "recovery mode" (available from lion 10.7 on, just boot while holding cmd+R) it's possible copy your clone back onto the system drive, but without being run 'inside' your current OS X installation. recovery mode is run from an invisible, secure partition on your boot HDD.

you use the restore function, but in reverse. copy your clone over to your system HDD.

cheers,