Ivan Vegvary wrote:
It's 3" ABS so it does not weigh that much. However, does no one
make a support system that installs within the wall (as opposed to
supporting it from below)?

I know that I can wrap it with 'plumbers tape' and nail the tape ends
to my studs. Easy to do where you can get a bite because of a
fitting. How about mid-length? It would be easy if they made a
'glue-on' (ABS) quarter circle with floppy straps that could be
nailed to the studs.
Checked with both box stores and ACE. Nobody knows of a better way to
support stack than to simply wrap it tightly with the metal plumbers
tape.
Any other ideas? Thanks god it isn't cast iron.

Use a sheet metal screw to secure the plumber's tape to the pipe?