The short answer is: No, there really aren’t any “water boots” that I can recommend for extended hiking while carrying a load. Essentially, they’re all modified running shoes, designed with drain holes and fast-drying uppers. So in a way, you’re kind of stuck with whatever system you have now.
I do have a few suggestions, though. One is to wear a pair of waterproof gaiters when hiking in stream-intensive territory. A pair of Outdoor Research Crocodiles ($58), snugly fastened, will keep water out during plenty of fast stream crossings. So too will donning a pair of Gore-Tex pants, snagging the cuffs around the hook-and-loop tabs on your boot tops, and again when making a fast crossing.
Otherwise, all I can suggest is that you swap out shoes when crossing a stream. It’s a hassle, I understand, but there isn’t another good solution. Maybe you can devise a system for keeping your water shoes closer at handhanging from your backpack belt for exampleand perform a quick swap. And of course, if you anticipate several stream crossings in fairly short order, just keep the water shoes on. Teva Rodium shoes ($80) offer full foot coverage and good watery performance, and would be fine for short stretches of trail.