Having recently upgrade my BeoLab 6000s to 8000s, I now have to consider shipping the 6000s when I sell them. Just discovered that carpet often comes delivered on stiff cardboard tubes with 100mm internal diameter; a handy 4mm larger than the 6000's external diameter.
Wrap the speaker in polythene or bubble wrap to avoid covering the speaker in cardboard dust.
The tunes are easily cut to length with a bread knife.
Most carpet stores will let you have them for free,