This recipe for veal stock is from "Welcome to My Kitchen: A New York Chef Shares His Robust Recipes and Secret Techniques," by Tom Valenti.
Heat oven to 325 degrees. Place a large roasting pan in oven, and heat for 5 minutes. Add veal bones, and roast, stirring frequently, until golden brown, 40 to 50 minutes.
Warm oil in a medium stockpot over medium heat. Add celery, onion, and carrots, and cook for about 6 minutes. Add tomato paste, sugar, peppercorns, garlic, thyme, bay leaf, vinegar, and wine. Bring to a boil. Reduce to a simmer, and cook for about 15 minutes.
Add the veal bones, and enough water to cover the bones by 1 inch. Return to a boil. Reduce to a simmer, and cook, skimming occasionally, for 3 to 4 hours.
Strain, discarding solids. Skim fat. Cool to room temperature, then store in airtight containers.