Adding bootable diagnostic partition(s) to 2010 iMac (sans ODD) (fancy Bootcamp question)
I used the AOMEI partition manager for the partitioning and cloning, but similar software will do probably just as fine.


In Windows, clone Disk 0 to Disk 1. This results in another bootable system on Disk 1. Disk 1 has three primary partitions (just like Disk 0). 
Create a fourth ~10GB partition at the end of Disk 1. Assign it letter Z.
Mount the windows ISO (using Daemon Tools or similar), then copy the contents to Z:.
Open the command prompt, go to the mounted image, then:

cd \boot
bootsect.exe /nt60 z:


(if it throws any error, make sure Z: is not open or used anywhere)
Create directory _bootimages on Z:, and copy all ISO files you want to be able to boot from.
Download EasyBCD and start it.
Add all ISO's to the boot menu, giving them descriptive names.
Under the WinPE tab, add another entry. Call it "Windows 7 setup" and point it to Z:\sources\boot.wim.


Restart, hold down Alt and click the "Windows" option that corresponds to Disk 1. A boot manager will pop up. Done.