So, I currently have a fairly stable system which I am quite happy with, however I would like to try some things that are somewhat tedious and dangerous to a stable system, such as rebuilding glibc to get the newest version. My question is, could I do this to essentually make a sandbox of my system. In other words:

• mount a empty partition.
• use dd to copy my entire filesystem to this new partition.
• bind the virtual filesystems to my current virtual filesystems and chroot
• or
• update grub so I could boot in to it.

would eithter of theese work?

Why not just install a virtual engine such as Virtual Box and do your testing in VM?

I, in contrast, prefer not to use a VM. Snapshot was invented for this.
LVM has support for snapshot as does btrfs. If you're a bit adventurous and happy to play around in gentoo, btrfs would be my suggestion. Rebooting with a snap is a doddle. Distros such as Fedora have this built-in. Just roll-back after a misadventure with an update.
Just make sure you have enough space in the filesystem - BTDTGTS.

The reason I would prefer not to use a VM is that if everything works correctly I would prefer to install the new system over my current.
I'm not sure how I would do that with a VM.

You wouldn't.

It seems to me that, in the long run, though, testing in a VM and then implementing the changes on your host machine might be less work.

It was just a thought.

One way to do this if you don't want a virtual setup, is to start with two blank drive and then install clonezilla on one of the disks and then install the "tinkering system" on the other disk.
With boot menu you select which disk to boot from. Either the system you are working on, or the clonezilla to backup/restore the "tinkering system".

Clonezilla can do disk to image backups/restores and only copy the used "clusters" of the disk, which makes it rather fast.
You also get a rescue shell fairly rich with support for drivers and filesystems by booting into command prompt on clonezilla.

No matter if you have a simple system in one single partition, or if you have a linux software raid setup over several disks/partitions and with LVM on top, clonezilla does the job.

If you have your bootable clonezilla drive on USB, then you can simply turn it off and your tinkering system can run without knowing of the other drive and without potentially damaging your backups.

I use clonezilla pretty often, for image backups, offline tinkering with filesystems and raid setups, and for deployment.
In most cases i boot clonezilla from network (PXE) and do backup/restore to a NAS server holding the backup files. Some systems don't boot from net, and then i have a disk in an external adapter with ESATA and USB to work with.

It works for Linux as well as Windows systems.

Try it: http://clonezilla.org/