I highly doubt there will ever be a fake DSTwo. Fakes try to atleast "some-what" recreate their original counterparts. the DSTwo has its own processor. If they make a cheap alternative to the DSTwo, i'd be all for it, lol. But no worries, I doubt we will ever see fakes, the 3DS is too close for a DSTwo fake.
(Unless theres DSTT's with DSTwo stickers on them. Don't buy from fake sites? Fakes are usually fairly easy to spot.)
Practically every flashcart on the market will pretend to be an R4 simply to exploit brand recognition, and it works too. I've seen many people buy into the fake R4s just because they heard of them through friends.
These fake R4s will usually copy something like the Acekard or the DSTT as the base system, and then implement an R4-style menu.
In any case, fake Supercards right now is really the least of your concerns, there were fake Supercard products in the past, but those largely predated the now infamous R4DS.
Why does (practically) every clone/fake flashcart be similar or have something in relation with the R4DS or R4i?
I have a R4DS which works great with wood firmware, but now using a clone R4i (for now) as I am now using a US DSi XL.
That clone constantly gives me problems!
Just hope my supercard will arrive asap...
By the way, (i know it shouldn't be posted here, but...) is it true that if you play Pokemon Black/White on the supercard (or any other compatible flashcart), you cannot use features like the livecaster or the IR battles via C-gear, even on the DSi/DSi XL?