I've been wondering about sundriver. The arrangement seems so similar to inside an RVT-H, you think it's a kind of clone?
AFAIK this is like a decent USB loader but I am not aware if the HD needs to be in the Wii like the RVT-H. I think it works like a wode in some way(hence the GC support) but more like a homebrew USB loader.
It's a complete drive replacement and can attach a 2.5in hdd directly to it, it fits nicely inside the console. I actually have one of these but I use the only officially licensed horizontal stand to house a 3.5in hdd.. the power from the wii is plenty to feed it also which is nice. You can switch between a limited # of games with the 4 switches that protrude from the disc slot or select the active game with pc software, but the best option is to just use the GC software to select which game to boot directly on the wii itself. Recently they added support for compressed images, originally you had to store the game with all of it's garbage data :/ wasting space.