I made my pattern strawberry themed, and I used all sorts of icons I could think of that relate to them :)
I traced my sketches onto a tracing paper, and scanned that in to illustrator to tidy up the lines. Unfortunately I don't have a tablet to redraw the lines, so mine turned out in this hand drawn style, but I think it suits the whimsy of the theme.
I really liked your tip for making the pattern seamlessly repeating, it was so easy to implement! This was my first try at this and I thought it would be a lot of fiddling.