1.Install without Re-partitioning
2.Boot from a non-bootable device
a useful link:
http://www.faqs.org/docs/Linux-mini/Loo … ot-FS.html
It's not a new idea, recently ubuntu wubi installer make great use of the technique.
I'm not sure what you're looking for, but pacman's -r flag lets you install Arch almost anywhere.
Mount your loopback device and `pacman -r /my/loop/ base`
thanks. pacman -r is very cool