GE has low amperage bus duct. (GE Supply)
Also, look in 'Electrical Advertiser'
They have lots of stuff, new, surplus, used, etc. Buss, plugs, breakers, xfr's, you name it.
I used the GE brand, which looks 'like' your link.
Need further info, call me. Redsey has my cell #, or e-mail (Johnhlec1@aol.com)