The last set in the Theros bloc, Journey into Nyx is now imported on deckbox: http://deckbox.org/games/mtg/cards?f=53175

Happy trading and have fun at the prerelease events!

The "prerelease set" has not been updated with the Journey into Nyx prerelease cards. I can only select Journey into Nyx as a set for these cards.

Is there a text list somewhere for JOU to allow ease of use to batch-add cards to our inventories/wishlists etc?

What I do is copy the set price guide from TCGPlayer.com (http://magic.tcgplayer.com/magic_price_guides.asp) and paste that into Excel. I then do the following formula in a new column: =CONCATENATE(4, ' ', <cell number>) where <cell number> is the first cell with a card name (usually A2). I then just autofill that down all the way and paste that into Deckbox as a deck so I can track my acquisition of a playset.

You could do something similar to just add the inventory, making sure that you get the column headers correct before importing.