I suppose a cloth diaper with a built in diaper cover would work, but that added to your disposable diaper is going to make it all very bulky and possibly very hot during the summer months. If there are leaking problems, I would suggest wearing a PUL plastic pant, but of course, they don't absorb, only block and hold a small amount of liquid. They too can become overwhelmed and leak. You could wear a very light weight cloth diaper over your disposable and then a PUL pant, but that too is gong to contribute to bulk.
If your disposable is leaking, you might want a higher capacity disposable. Taping the diaper might be a problem area as well. The right disposable shouldn't leak until it is overwhelmed as any diaper combination will leak if there it more liquid than it can handle.