Recently, I have made a number of USB sticks to install OS's (several Linux flavors, BSD, Windows) from, on machines that didn't have CD drives.
Now, I would prefer to not overwrite the install USB sticks all the time, since it's handy to have them, but neither do I want to pile up USB sticks that I only need every 6 months.
It would be great to have a bootable USB stick that fires up some minimal system, lets you choose an ISO image and then reboots from there. How would I go about this? Do I use some minimal Linux? Is there some kind of modified / specialized boot loader? Can I set up GRUB to do this? Should I use virtualization?