Versions
There are two versions of the SuperPass, just as there are two versions of PassMe - one, the original SuperPass, works on original firmware systems. A more recent version, the SuperPass 2, has just been released.
Company Site
The company's main website, http://www.supercard.cn/.
User's Comments
I'm afraid I don't know a great deal about the SuperPass's construction or history; I use it in combination with the SuperCard CF without any difficulties. Please note, however, that I didn't then use the SuperPass to flash the system; as a result, over about a month or so of use (including daily insertion/removal), the system now instantly ejects any cart added to it; it's very possible that insertion/removal of the SuperPass can damage the hardware. Note this is a SuperPass ""original"" version, not a "SuperPass 2"
The SuperPass and SuperCard are snug fits - they're built very close to the limit of the size of what will go in, and as such, feel like very tight extensions; they're not flimsy, and so now, I keep them in all the time. I've had to go out and buy a second DS to play commercial games on, though. 
Both the SuperPass and SuperCard are solid, semi-chunky bits of plastic of solid construction. I ended up buying them pretty much for that reason - and bought them in a combo pack with a 1GB cart from... who knows where. I've forgotten. Very happy with both of them, however. (gblock at ctoforaday dot com)
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I have used the SuperPass2 in conjunction with the SuperCard CF to successfully flash my NDS system using the FlashMe software. Thus removing the need for any pass through device.