Are you doing enough rugs to really need a spinner?
I would guess you'd need to be at Hagopian volume levels to make the risk and cost of those things worth while.
Dusty and Monahan give the impression that the country is flooded with those tubes when in reality I'd bet there are less than 35 in use.
Do you have a OP machine? Take a Tuuway pad, sew in about eight marbles in a line between the plys and you got a Rug Badger that does other stuff beside collect dust.
IMO unless you go all out and are willing to spend all day in the plant making love to your fine textiles, don't bother.