All of the brown sauces have their roots in basic brown stock. Although veal stock can be either white or brown, 'brown stock' typically refers to a mixture of beef and veal. True veal stock is much more difficult to make or obtain in the US, because we don't eat as much veal as they do in Europe, making it harder to find bones and much more expensive. Wolfgang Puck's ego aside, the traditional base is brown stock, not veal stock, which would have much more subtle uses than burying under other strong meat flavors.
When I make a pot of stock, I divide it into 2 batches.
First batch, I slowly reduce until most of the water has evaporated, and I have a thick glaze that coats the back of a spoon. When I chill this, it's a firm jelly. This is called viande de glace, or meat glaze. Freeze it by the tablespoon. I use it 2 ways. Add a tablespoon to a reduction sauce to greatly enhance both the flavor and the texture of the sauce. When I need beef stock, I just reconstitute a tablespoon into a half cup or cup of water, depending on the desired strength.
Second batch, I enrich further with more meat, onions, tomato paste, and thicken slightly with flour. I freeze this in 1/4 cup or 1/2 cup containers. This is Sauce Espagnole, and is the basis for several of the classic French sauces. When I need demi-glace, I reconstitute some of the glace and add it to some of the espagnole.
This way, I only have to store 2 sauces (glace & espagnole), but I have a world of sauces at my disposal.