ISO Worcestershire Powder
You can order some from malabar.
This is an unconventional retail consumer ingredient, but its widely used in the meat processing industry, so you have to shop where the meatheads get their supplies from. Malabar should be small enough to handle tiny minimum orders...unlike McCormick or the other multi-national seasoning houses.
The prices were different at each site and you can order the powder in small kitchen size shakers or in bulk.