I have made egg custard in large trays and I am sure you can do the same with creme brulee. It may not be the most perfect looking but can still work with a little ingenuity (in my humble opinion
Make it by quadrupling the recipe (I am a big winger when it comes to bumping up recipes and have never been disappointed with the results).
To serve I would do the following (I have done this with custard with great results).
Cut into medium squares or rectangles (think first about how much you would like the serving size to be prior to cutting it). Now sprinkle sugar on it and torch it (do this after you cut but it's still in the tray). Now slowly lift it with a flat spatula and add it to the plate. Add some fresh raspberries on top of it and on the plate and garnish with mint or shaving of white chocolate or anything else you like. Any imperfections of cutting and moving can be covered by positioning the raspberries correctly.
I make my custard this way. I don't burn the sugar but instead make a glaze with orange juice, orange zest and sugar and drizzle that over the top of the custard peice and place some fresh mandarin oranges on it and serve.