I found something cheaper! Well the hull at least, this is called the HFM Deep Dive, dives dynamically just like the Seawolf, but instead it has a non-cylindrincal hull (can't dive as deep) All you have to do is throw in the radio, maybe motors slap, on some decals (included) and off you go! The hull costs just over $100 US at around $133.



You have to order it from the UK though:
http://www.model-dockyard.com/hfm/deep-dive.htm