I am also curious about this. I really like how the previous ones match the MBA design so perfectly. It seems like such a shame to have a perfectly good 128gb SSD just siting around not being used for anything.
EDIT: I contacted OWC support and asked them. As expected they told me they don't know the ETA for it. However they did tell me it is indeed coming eventually. Now it's just a matter if I should wait for it or buy a generic enclosure from somewhere else that doesn't match as nicely.