OS X Mavericks :: Sync Mail Database Between MAC Computers Without Using IMAP?

The normal question is can I sync  Apple mail database (folders) between two MAC computers. The answer is always use IMAP, but unfortunately IMAP is limited on space to store historical emails. I keep mailboxes (on_my_mac) with thousands of emails and attachments that take up a massive amount of space, well beyond any IMAP server allowances. I keep these in order to search conversations that span over many months and sometimes years.  

I use GoodSync to sync my normal folders from my MAC Book Pro and my Mac Pro desktop so that I can have the same information (in real time) when working from home on my big machine or at the office using the laptop. This is great except I can not sync the email. I use Outlook 2011 but would prefer to use apple mail if I can sync the two computers (Sync'ing Outlook 2011 is even more impossible). 

I also do not want to start and stop my email clients to make this happen and worry about which MAC is running mail and what direction to copy the entire folder structure just to have to follow that up with a new re-build of the index. 

Also keep in mind the amount of data - Cloud based solutions are dependent on Internet connection speed (days of initial transfer time and hours to sync) and if I am on my laptop without internet connection, say on an airplane, I would be out of luck so I need the information local on each computer.