Okay, I can't resist this!  Marc Kaufman and Robert Linnstaedt
have commented on the reason for calling them "cobs".  Marc said,
"It's because they look like corn cobs, and not like pickle barrels."

May I add:  They aren't called barrels simply because they are not
barrels.  The cobs (or rollers, if you will) are solid; they're not
created from staves, like a barrel.  The barrels in barrels organs
really are barrels -- albiet, long skinny ones.

As to e-Bay being the appropriate place to sell MM related items,
there are a lot of MMD members buying and selling on e-Bay.  And not
at bargain prices.  I've seen some very unusual items and some items
that are selling at prices higher than most antique dealers.  Perhaps
some buyers and sellers could give us some comments on their
experience.

Regards,

Craig Smith