closest I can find.....
http://site.hooksandlattice.com/product-specifications/channel-sign-bracket.pdf
It may just be custom. Earlier in my life when I was a machinist we would make items like that all the time for crazy architects who couldn't have any off the shelf items and wanted everything to be unique to their design.
got several of those projects sitting on my desk where you try to make the design into reality, at least nothing is boring
I hope they pay their bill better then the ones I was dealing with. Had to send a few of them to collections before I got paid. Seems they want the world but hate paying for it.