It looks like 8GB SD cards will be hitting the market soon. Pretec claims it has developed the first of these cards. The card supports SD 2.0 and is not backward compatible. Users can currently order one card for sampling purposes. The company has also created a 16GB flash drive which is claims is the biggest of its kind, but that is clearly false since drives exist well beyond 16GB. At any rate, Pretec says the drives will be ready for mass production early next year.
I’m sure this thing is going to be expensive. A better alternative might be to stick with a smaller card and simply use a portable hard drive based photo viewer. That way you can get about 80GB and about the same price.