Hey! Another solid brick homeowner... well, the house is solid brick, not the homeowner. Sorry. I have one that was built in 1900 and has taken extensive rennovation over 20 years (including foundation rebuilding).
There is absolutely NOTHING that you will ever do to this type of house that will be either inexpensive or easy. Remember, you are working with bricks that are stacked like dominoes, so where you touch one area, you can sometimes structurally effecting another area clear over on the other side of the building.
Your house is called Twelve Over Twelve in the world of masonry, and is actually constructed like a huge, double-walled chimney. In your case, it sound's like the crossed masonry walls through the center of the house also add vertical support to the exterior masonry walls. If you start poking big holes in those interior walls, and you don't get it restructured correctly, the unbelievable weight of the exterior walls can begin movement that will ultimately ruin your house.
As someone who has watched a very excellent mason work on this home for many years, my strong advice is to FIND A VERY EXCELLENT MASON. Messing with those brick walls is no job for an amateur. I'm sure you'd like your house to still be standing in 2004.