I saw a pair on a big Skater a few years back. Sage makes some fantastic products, but I don't know if it's a solution to an existing problem. It would probabaly hold up a bit better over 1K HP but the shaft/rudder systems are working pretty well in those applications.
The drive does slide up and down. The shaft is sort of like a 2/3rds length "arneson style" drive and it has sort of an outdrive-looking case above that moves it up and down and steers.
It does have the ability to swap gears so you can do ratio changes that you can't do easily on a 6 drive. Probabaly a benefit to racers more than the average guy.