http://www.ottllc.com makes a storage system that will hang barrels about anywhere. I got a couple of things from him ( Mike Sirois) he was nice to deal with.
I have to many barrels to try and buy that many storage units.
I made my own hanging system. I used a 3 in piece of oak and notched it out to just over the size of the barrel and then made a cut that the lug would set into and then dadoed the top with a 3/8 wide grove agout 1/4 inch deep that is in line with the hinge pin hole when the barrel is hung up.
I got a packaage of dowels ( 5/16 I belive for contende and 3/8 for encore) from home depot to put one thru the hinge pin hole when I hang them up,
I have about 35 barrels now and I need to make another holder, mine is about full.
Oh BTW, I cut some of the notches larger so I could hang my frames up also
Neal