Well if there is no case for Dell yet, you can always get one from this guy.
http://www.thepouch.com/
I order one way back when, for my Libretty. I made a phone call, he actually pulls up the measurement for Libretto and he says, yes I think we have it in stock, if not we just going to make one for you. Very nice person.
The thing itself is pretty cool. nothing fancy, but a good handmade wet suit for handheld. It's more of a "water resistance pouch" But I love using it for my libretto out door. plus it's cheap