I am curious yet confused, what and what does not need to be compile for multilib on a system that wishes to sport 64 and 32bit binarys?

Does the system really have 2 versions of every package? or just a 64 version of the binary and 32bit version of the libs?

Take a look at the CLFS instructions --> http://trac.cross-lfs.org/ and the CBLFS instructions --> http://cblfs.cross-lfs.org/index.php/Main_Page

No you don't need two versions of every package. You only need 32-bit versions of those packages that you need 32-bit support. For example, if you want to use Acrobat Reader, which is only available 32-bit, then you'll need 32-bit gtk+. Since you also probably want to use other 64-bit apps that use gtk+, you will also need 64-bit gtk+. On the other hand, you might want to monitor the sensors on your mobo. In this case, you only need the 64-bit version of lm_sensors.

I have already looked at those (thanks btw) so 32bit apps can't talk to 64bit apps I am guessing, okay wait then, I have another question, if this is essentially a 64bit with 32bit support then why have lib the 64 bit lib dir and lib32 the 32bit lib dir, the way it is done in the book looks like 32bit is still the primary and 64bit looks like it's been tacked on

The FHS requires 32-bit libraries be installed in lib and 64-bit libraries be installed in lib64 on x86_64 machines. Even if you never install or plan to install a 32-bit library, the 64-bit libraries go in lib64. For the CLFS x86_64 multilib instructions the book is FHS compliant. For the "pure" 64-bit x86_64, the CLFS book is not.