Have no personal experience with Inca lifts, but search this forum. There have been some very negative references in the past.

You can try Auton for plasma flip down lifts.
[Link: auton.com]

These things take up a lot of room, so I hope the house boat has a lot of overhead space.

Haven't used the flip down unit,but their lifts for in cabinet are good.
Good Luck!

ps - don't you just love it when your customer sees "something cool on some show on maybe HGTV or maybe somewhere else?"

bob