I have read over everything now. My brain feels like it has just finished Thanksgiving dinner and needs time to digest everything. Suffice it to say, I am still ruminating on how best to proceed.
By the way, while on my reading quest to get up to speed, I stumbled across the MPI Design Discussion topic. I thought I would link to it here since it has a fairly comprehensive (albeit lengthy) discussion on the thought process behind the current MPI implementation.