I'm working up a reply to Peacebang's comments about trench coats but having a terrible time finding pictures.
I have found something that all gown-wearing clergy would want: something comfortable that breathes in the heat and travels well. If you can afford it, and are willing to order from Germany. Dan Harper, I know you're interested . . . .
Prussian-style microfiber robe (Google "Automatisch" translation)
Talar preussische Form aus Mikrofaser (German original)