This goes in the wall directly to an intersection pipe (T) fitting.. was hoping for a creative solution less evasive. The trap fittings are some older standard and nothing new fits.
What older trap fittings are you referring to?
Are you saying there is no easy way to remove that trap assembly shown to allow it to extend further out? In other words there is no screwed connection into the tee in the wall that can removed for connection of a piece of pipe?
You can cut it flush and then cut notches in the piece that is left over in the fitting and pry it out. If you cut to far and through the hub of the fitting that will be bad. You could also cut it flush and get an 1 1/2" easy out that goes on a drill motor.
There's a multitude of videos showing different methods of removing a glued PVC pipe from a fitting. Different types of heating approaches appears to be pretty popular. I wouldn't recommend any which uses an open flame.
I noticed a "This Old House" video shows using a tool made for it.
I suggest you review the different methods and pick the one you'd be most comfortable with.
Looks like you could just cut the down rim elbow right at the end of where the sleeve goes in, then carefully cut off the ring from outside the sleeve. Then just glue on a coupler and you can extend as you wish