There isn't much that I can think of off hand for an intermediate boat. Usually the next step is to build one yourself. A .21 powered nitro boat would be the next step, either an inboard mono hull or a 3.5 tunnel hull but the motors are getting hard to find at the moment. The only one that I can think of might be the new ProBoat Shockwave 36 but that wouldn't be a whole lot faster than what you have now, maybe 5-10 MPH quicker. If your pockets are a little deeper, a Gas powered boat would be a great move up in the boating world. Warehouse Hobbies sells some nice RTF boats, from around $700.00 and up.