I like to use this: http://allrecipes.co...mix/detail.aspx to replace the Onion Soup Mix. It tastes basically the same and, possible gluten issues aside, it's not chock full of artificial flavorings, colors, or preservatives.
I love this recipe! My 8 year old was asking for meatloaf for dinner tomorrow. I think I'm going to use this. Kills 2 birds: no gluten and no unnecessary chemicals! Thanks!