Sorry, but such system-wide changes do require some form of root involvement, if just for sanity's sake. Perhaps the nearest to what you want is to create a virtual machine and play in it, or something like Fedora's mock, the mechanism used to create a chroot populated with the required tools to build a package. Probably other distributions have something similar. The whole namespace development in Linux promises help here, there is a series in LWN running now (part 1, part 2, part3part3, part 4; part 5 is still subscriber-only). But namespace setup will still be a root responsibility.