Something like gksudo would be what you would use to use this application to do a GUI install, but what specific program you use to get root for running a gui application does depend on the distribution. (For example, I'd use 'sux' to become root and then run it, on my system.)  But in general no one should be running GUI PIP as root: for root installs you should be using the distribution package manager.

That said, the standard way of "elevating privileges" in unix and mac is to use sudo.  You'd just add 'sudo' to the front of the pip command string when you call POpen.  But I'm not sure this is a feature that should be supported, since in interferes with system package management