I'm thinking (not sure) you'll have problems fitting a 14' kayak into a 19' B. It'll also beat up the interior wood work unless you use a lot of padding and care when putting it in and out.
But I have seen a 1st generation Roadtrek 210 (the one based on the older 21' G-30 extended long wheelbase van) that had fully separate twin beds inside the rear doors that would probably have enough length. They're not easy to find, tho', and may require extensive 'reconditioning'. The van's amenities would be pretty much inaccessible with the 'yak on board, too. I think I'd go with a 19' B and a trailer.
Jim, "Mo' coffee!"