[Henry]

Anyone know if there exist panniers (both sides behind) that are water proof (of course) but also more aerodynamically designed and the most important: they can be locked, so you can leave your things in the panniers safely. Only in the future?

[froze]

They do make them but I've never known any touring folks that used them. Just do a web search by typing in the search: locking bicycle panniers and a whole bunch will come up. The water proofing comes from either optional water proof covers, or a few bags are water proof that don't need the covers. If you're touring aerodynamics is something no one worries about because your not travelling at 30 mph, plus you need the storage which takes precedence over aerodynamics.