All the wired jacks in my house support two lines (inside and outside pairs) which home run to my wiring closet. Thus each jack supports either two single-line phones or one two-line phone, and I have both types. In addition, I have a two-line cordless system with around six two-line handsets.

I upgraded the cloned line from VOIPo, so the two lines are independent. A single PAP2 connected to the wiring closet drives all of it. The base station of the cordless system is simply connected to one of the wired jacks. Most of the phones are pretty old, but everything seems to work.