The operating system is modular. It consists of a kernel, an initrd, and the modules. The base modules 000, 001 and 002 are maintained by Fanthom. The desktops are separate. Maintenance involves compiling or downloading each slackware package individually, unpacking into a folder, running a cleanup script (different for each module) and then repacking it into a single module.
So the answer is actually yes, you can recompile Porteus totally but not as a single event. You need to compile the kernel, then the core, then the desktop modules. After that there is the addons such as printing, skype, browsers, video drivers etc.
How do i become super user?
Wear your underpants on the outside and put on a cape.