It's not that difficult to draw your own pattern. Get a pair of shorts that fits and fold it into half and trace it on a piece paper, remember to leave seam allowance, do the same for front and back, cut it out and there you have it! You just made your own pattern!
Then I put the patterns on a big over-sized t-shirt which nobody can wear (don't ask me how we got it!) and cut them out. Next, sew the 2 front pieces together at the crotch and do the same for the 2 back pieces. After that, sew up the sides to join the front and back pieces together. This is my trial version which I hand sewed... except for the stupid mistake made in cutting the fabric, it looks quite good!
And I made another one for the youngest prince from an old blouse "donated" by a dear friend! ^.^
Added in a pocket just for fun!
Not forgetting a special touch...
Add in elastic bands and it's done!
And don't forget to iron them to give them a more "professional" look! :P