Darkstorm is right... unfortunately :( although considering the ending of the anime and if you read the fan translated manga the story is only the same up until a certain point and then the anime steers off and has an alternate ending to the manga so I guess it's not impossible for thier to be a season 2, but really, after that beautiful ending in the anime, I personally think it sort of better to leave it be as it was in my opinion one of THE most fulfilling endings I've ever seen and that's including books, movies etc... read the fan translated manga if you want to continue on with the story, you can find the scans on www.onemanga.com but it isn't finished yet they are only up to chapter 84 out of 107 last time I checked and a new chapter usually comes out every week or 2, hopefully that should keep you busy, one thing though, it's a rare case but the manga really isn't as good as the show! hopefully that should keep you busy for a while ;P
I don't understand the "box set elfen lied 2" listing at all. It's the first, and only, series and is listed at running 325 minutes, the same as the region 2 boxset... so it doesn't even have episode 10.5 unless it's in the extra features.
That box set is a region 1 listing though. Maybe there was another boxset region 1 release which differed from this and so they called this "2" simply to differentiate? I don't know... it's confusing!
I do not see how they can continue this story without ruining it, much like the original Highlander movie being far superior to everything that followed it. The ending was perfect, it should be left alone unless they are going to follow a different characters story that may intertwine with the group at some point.