Also, future mockup!
This sort of effect would be insanely easy to pull off. Basically I'd take water(in this case from pics1) and give it a semi-transparent fill(like 80% opaque or so). Then I'd take the sky/npcs/players and duplicate them under the horizon, vertically flipped and render them under mode7. Very, very easy to do and I can't wait to get to it. I want to do an entire water course with this. This effect, with some nice parallax sky scrolling... suhweet.
Also, sky was just ripped from New Super Mario Bros for mockup purposes and the noob in a kart was pulled from someone elses attempt at mode7 in Graal(I think obviously edited from Super Mario Kart).