Well, I'm not a CI so this is just coming from an end user that's currently servicing about 16 different CATV devices. I'm not familiar with commercial RF distribution equipment, so this is just with more readily available stuff that I use myself.
First, you're going to want RG6 throughout. Second, I would split the feed in the old wing, one line to the old headend and the other line to the new headend. Before the splitter and depending on incoming signal strength, I would probably install a quality amplifier.
At each headend I would put in something like the Channel Plus DA-8200BID, which is basically a lossless splitter (I tested and it only adds about 1db to each output) that also supports 2-way digital cable boxes. However it's only 8-way, so you could either add another splitter before each and have two 8200's or split some of the outputs 2-way (thus why you'll likely need an amp at the beginning of all of this). Channel Plus products are good quality and won't give RF interference issues like the cheaper stuff.
Of course, this all works better if you have a great cable signal to start off with. If it's crummy, then splitting this many times is not going to work well no matter what quality equipment you have.
Now, there are other solutions as well. What you pretty much need is a small apartment/condo distribution system. There are also all those fancy modular distribution panel systems out there, many designed to handle this many devices from the start.
