Well see that is the question. The Wii will do rgb/scart, but only pal Wiis. The NTSC Wiis do component. Since these aren't advertised as NTSC only or PAL only I have to assume that they will do both scart and component. I found a thread on psx scene where someone had modified it to work on the ps2. Apparently it works just fine, the only issue is it has trouble with low resolution interlaced modes and the 5v on the ps2 av out isn't enough to power it so you have to use a usb cable. It'll still display interlaced modes, it just has some screen tearing. They did it on a NTSC ps2, so that means they'll do component, which means it could be cobbled into a xbox adapter, which is nice since no such adapter exists.
Oh and it gets more interesting. There are several articles telling users of the device to go into the Wii's settings and set the resolution to 480p or else it'll output 480i. Now if those are written for ntsc consoles, that means that the adapter also does either s-video or composite, possibly both.
So taking all that into account it's a 4 dollar rgb/component/whatever 2 hdmi adapter that's not much larger than the typical av out on most console cables and can be powered by either the console itself or the TV's usb port. That's a pretty nifty find. I saw some screenshots of the inside of the adapter and it'd be easy to solder on component connectors or just remove the wii av connector and solder a different one in it's place. Even easier, the av port of a wii is just a pcb used as a blade.... so whip up a breakout pcb and send it off to one of those pcb mills.