Joe, if you plan to build one from the ground up, you will need a lot more time than ten years, just to find the parts. Much of a 701 PBX is comprised of factory-wired shelves, trunks, and line relays. To assemble the whole kit will be a logistical nightmare.
I suggest that you talk to some of us who have working switches and try to find the major parts already built, then find the appropriate power units, trunk units, ringing machines, tone supplies, line finders, selectors and connectors, and then wire them together. It'll take at least a decade just to do that.
The alternative is to buy a complete 200-line switch frame and in a few months you will have noises coming from it. You only need to drive to CT to get it.
I'm not sure who told you that a 9' high frame is what you need, but you have the wrong info for a PBX. Their frames are 7' tall, including the base and top cable rack. Most collectors reduce them to around 6' high to fit into residential areas, by cutting off the top gussets. I had to find surplus channels with gussets, and weld them back on the tops of my frames to get them back to their original height. These frames are not self-supporting, and once they are populated with switches, unless they are fastened to the wall or ceiling with cable racks, they will fall over or collapse.
