Des Plaines Hobbies has had the grab irons in brass in the past. They should be part number OSA1001 if I recall correctly. I do not currently see them listed on the DPH website, which normally means they are out of stock.
Also, P&D in Detroit used to stock them along with most of the OSA lineup. On the P&D website, they would be listed under Custom Finishing detail parts, with part number CUF1001. Custom Finishing is the original manufacturer, and Des Plaines bought the O scale part of their lineup back in the day. At any rate, they are also currently not listed on the P&D site, which typically indicates that they are not currently in stock.
A phone call to either store might shed light on any plans to run new parts.
Hope that helps,
Jim