In chrome, you can make a shortcut for a profile by providing a flag --profile-directory="YourProfileName"
It will be created if it doesn't exist and you can even set it to point to a TEMP folder for throwaways.
Ah, didn't realize that. Thinking about it, I've only used this 'hack' to have two different gmail accounts open at the same time (one in normal, one in incognito).