Ken, It's not that difficult to make your own steel sides with Evergreen sheet styrene, especially now with Archer rivets.  This one was interesting as it has two rows of rivets per panel.  I've done it several times, the most recent is the ACL O-24 I finished a few weeks ago.  I've been asked to do an article on this for SAL/ACL modeler.  This car started out it's life as a P2K 50 SD boxcar at 10'-6"IH but now it is an ACL car with a 10'-1"IH.