Why is it not possible to find pnp bipolar and n channel mosfet transistor arrays in IC package?
Of course they exist. Here are PNP transistor arrays: http://www2.mouser.com/Semiconductors/Discrete-Semiconductors/Transistors/Bipolar-Transistors-BJT/_/N-ax1sh?P=1z0y4cnZ1z0y25uZ1z0rupj
I'm sure you can now find N-channel MOSFET arrays too.