My aunt brought be back this awesomely beautiful little pill case from her trip to Italy last year. It only holds about 6 enzymes but it is rather flat and fits nicely in my smaller purses (and even my wallet's change pocket). They make similar cases here, but they are just nowhere near as pretty. You can usually find them in your local drug stores, near the pharmacy counter.
As far as finding something sturdy, I think you'll just have to resign yourself to the fact that you will probably have to replace your pill cases every once in awhile. We use them so much, they are bound to break eventually. <img src="i/expressions/face-icon-small-smile.gif" border="0">