I highly recommend watching at least one-half minute of the 16S boat video, brought a big smile to my face.
http://www.youtube.com/watch?v=OBTt_NZpyfs&feature=youtu.be
[youtube]OBTt_NZpyfs[/youtube]
Rated for 17S, recommended voltage is 16S. If using the 3.6V - 4.1V per cell protocol, thats 57.6V - 65.6V for the pack. It makes sense that the boat ESCs would have higher voltages available sooner than plane/heli ESCs. RC motors are typically terminated in Delta so they get the max RPMs per volt, Planes/helis are very weight sensitive, and going to a higher voltage can put a limit on how many aH's you can load the plane with, so...lots of RPMs from fairly low voltages. I'm guessing boats would be less weight sensitive.
Like most boat ESCs, this is water-cooled from the boats high-speed forward motion ramming the flow (*no pump), so...AJs computer liquid-cooling experience may be useful here?
At the 1:33 minute mark, I notice he's also using an outrunner with the recently-discussed water-cooled motor baseplate, they use two separate non-contact thermometers to verify the temps of the motor, controller, and batts.
edit: in the RC chat, there will be car versions with finned heat-sinks and possibly integrated fans. Be aware these are spread out for heat dissipation, one guy quoted approximately 6" X 3" (roughly 150mm X 75mm)