Is it possible to do this on one computer to use in another - without an external app?
In other words, can I put the Windows 7 disk into my Macbook, and use bootcamp assistant to make an ISO image to put onto a flash drive to use in my (eventual) 2012 iMac - without changing bootcamp on the Macbook?
Would this be basically the same procedure as mentioned a few comments above?
Thanks for any help!
The way that I did it was a little bit different. You can use the Disk Utility application that is already installed on your Mac to make a .cdr file, then convert it straight to .iso from command line.
1.) Open Disk Utility, click the DVD drive on the left hand side, select file > new > disk image from "<name of disk>".
2.) Next save the image to your Desktop, and select DVD/CD master in the "image format" drop-down menu. Select "none" for encryption.
3.) This should leave you with a .cdr disk image file on your Desktop. You can now open a Terminal window (easily found searching spotlight for "Terminal"). After a terminal is open, type
cd ~/Desktop
hdiutil makehybrid -iso -joliet -o win7image.iso win7image.cdr
Though, you must change "win7image.iso" and "win7image.cdr" to whatever you named the .cdr image file in step2 in the above command. It takes a few seconds to process and then you should have a .iso file that you can put onto a USB drive that Bootcamp will recognize.
One side note: do NOT create the bootdrive through Bootcamp with the newly created .iso until after you receive your new iMac. You will want to make sure that Bootcamp will load the drivers specifically associated with your new iMac and not with your old Macbook.