Yeah, HUGE profit in the extended service plan market.
Be sure and ONLY go with an OEM ESP.
MOST of the aftermarket ones out there aren't worth the paper that they are printed on.
And yes, if I was buying a new boat, I'd have the dealer throw in an ESP as a deal clincher (in fact, I have done that three times so far). Just don't let on about it until AFTER a price has been agreed upon, otherwise they'll just pack it into the price.
Good luck!