""""""""(one nice addition would be to have a extend distance option to create pipe longer than the input curves on both side, it can help to trim surface later for manual filleting / blending)""""""""

There was also the "Wires" script from Max, with an updated version named Wires2 from mkdm

The wires 2 script allows picking a "Profile curve" and includes the "Extend" function you describe

However, it DOESNT do what pipes does, by using a PATH. Only tangent connection to 2 pick points

If somebody could "COMBINE" these 2 scripts, it would do exactly what is requested.

I am not capable of that. Always tried to avoid asking Michael to do extra work

https://moi3d.com/forum/index.php?webtag=MOI&msg=8301.27