The only thing I've seen is actually a memory card booster, but not a 16 MB memory card at all. The one I saw is mad by innovation technologies or something like that. And, indeed, you will need to already have a 8 MB memory card. But according as for what I read, it can even give you a total of 24 MB to save data. Yet, have no idea how good this accesory is. Hope this helped a little. But this is only what I saw, maybe there's a 16 MB MC out there, but I still don't know about one.
EDIT: Now I've seen that there's actually several of these boosters. Still haven't seen any memory card with all that space. However, be aware, as for what I've seen, these accesories tend not to work, thus, meaning a waste of money. Yet, my recommendation for now is that you should buy an original Sony MC. They are freaking expensive (40 bucks) but at least, they are safe and work allright, and besides, 8 MB is a lot of memory to save PS2 games, if you didn;t know that. So you'll probably won't need such boosters either. Up to date I got only one Memory card and it works fine to me, and I still have a lot of space available.
EDIT 2: I am so awsome.... now I checked out more and I found out that a mc is just 25 bucks
besides, a new pack has been released by Sony and it is a Blue and red memory card pack, and it's only 40 dollars for 2 memory cards. That's the best deal I've seen. I think I'm gonna buy that
