Buffalo have released an external SSD case that is designed specifically for the ASUS Eee PC 901-16G. The external SSD case works just like a portable USB drive but rather then a moving disk inside, it has SSD’s.
From what I can work out in the translation, the idea behind this is to buy the case (in which you have to buy either a 32GB or 64GB SSD with) and then switch out the 16GB module replacing the internal one from the Eee with the larger capacity (32GB/64GB) model which then gets you a lot more storage. You then use the external SSD case as “extra” storage for your Eee PC.
It seems like you have to do it this way as there is no option to buy just the case alone. Prices are not too bad at $129 for the 32GB model and $228 for the 64GB model. It is expected that they will go on sale next month in April.