Finding Dignified, Ready-to-Wear: Extended Sizes and Tall Options

I normally buy from made-to-order shops that offer customization, but it looks like I'll need funeral attire soon. I know of some ready-to-ship brands that are US-based and ship to the US that offer extended sizes (I'm an XXL), but I'd prefer a brand that also offers tall women’s sizes. I am also open to simple-shaped dresses that don't have a defined waist. Not just black but navy or dark brown.