My Grade 4/5/6 students recently finished these large scale paintings for our school's annual Winter Concert. These are done on 18 x 24" paper. The kids first measured out a thick border (about 2" or so). Then, inside the border they drew a winter or holiday themed image of their choice. I encouraged them to keep it large, bold and simple for time's sake (we were on a bit of a time crunch to get these finished in tome for the concert!). Of course, a couple students went super small and detailed and didn't manage to finish in time as a result unfortunately.
Once everything was painted (using tempera), they outlined their image with a China marker (my new obsession though they are a pain to sharpen). Once they were finished painting and outlining them, they had to include some type of pattern in the border. Once dry, I added glitter to the border and hot-glued on a large red festive bow.
Here they are hung up at our venue for the concert.