November 2015,
Darren Bos fitted a wireless controller intended for off-road trucks. It floats and it's waterproof (well, after he tested it, found the leak, and reset the gasket) and he keeps it in the wheelhouse of his 40-foot Benford schooner.
He paid $12 including shipping (I just found it for under $9) and, as he says, "I could buy 24 more of these without reaching the cost of a marine unit."
Darren bought his on eBay, but I found this link:
http://www.aliexpress.com/popular/remote-winch-switch.html

Seems there are dozens of these remotes out there -- a matter of finding one that seems to have the right feel.