I have the same problem! I'm 5'2" so it's quite a big problem haha. I find the boy's section of big department stores, supermarkets etc is quite good for casual stuff. Otherwise you could try taking apart a pair of pants, cutting the panels down to your measurements and using that as a pattern (for yourself or a tailor). A friend of mine who is also short orders a lot of his stuff from online retailers in East Asia, apparently they have a good range of smaller sizes. Hope this helps!