I make my own seitan. The taste and texture varies depending on how you prepare it. Boiled seitan has a luncheon-meat-like texture, and baked seitan is a little more meatloafy. Adding some anise and rosemary gives it a sausage flavor, and adding minced dried mushrooms (especially porcini), along with the soaking water used to reconstitute them, makes it taste beefy. I always add garlic, and usually some tomato paste or soy sauce for color.
I have a hunch that a good dollop of Marmite will also make it meatier, and plan to try that the next time I cook up a loaf.