It may not a good idea.
As it may cause hassle to connect if it is too short.
There is reason, why extra length left at there for most conceal piping.

A simple boxy wooden or plastic decorative item of cover may do the job easily, depended on one creativity then, instead need a dummy air-cond.
I only hear people install dummy cctv, never hear people install dummy air-cond.

Then design an elephant type of clock/paint, the 6inch long may be painted as elephant nose...

Depended on craftmanship, it can be nice looking and creative as well.

PS: pop up this idea from caryon shin-chan...